Search Results for 'espin telescope'

[Daryl Dobbs]

Good  program and an interesting telescope, prism instead of a flat was unexpected but nice to see it restored. I wonder who recoated the mirror and I wonder if it was tested to see how good the figure was. No centre spot on the mirror to aid collimation.

[Mr Jack Martin]

Telescope restoration project 

http://www.bbc.co.uk/iplayer/episode/m000x90x

[Andy Wilson]

Hi Alla,

Hopefully someone with specific knowledge of your setup will respond, but I thought I’d give a few general pointers.

You’ve not mentioned whether you have been able to polar align your mount. With that type of telescope mounting the first step is to get the polar axis aligned. From the look of it, that mounting has a polar scope to help get good alignment.

Then you typically go through a one or two star alignment, where you need to know a few bright stars.

I’ve found even with aligned GoTo telscopes, they won’t always get your selected object in the eyepiece. Sometimes they are spot on, but otherwise they’ll get it close and you then need to look around a bit, usually with the help of the finderscope.

If you don’t find someone to visit, then you may have a local astronomy society who can help. Looking on our page of Local Societies affiliated to the BAA, I see there is a North Essex Society.

https://britastro.org/links_affiliated

https://www.northessexastro.co.uk

I’m not sure how far they are from you. During normal times, some local societies hold telescope workshops or star parties, where you could get some help.

Best wishes,

Andy

[Alla Bonn]

I am looking for an amateur astronomer or a telescope engineer who could set up my telescope for me at my place of residence, I am happy to pay a good fee for such service.

I own a Celestron ( https://www.celestron.com/products/advanced-vx-8-edgehd-telescope ), and keen to start using it, but struggle to set up telescope’s tracking system.

I live in Billericay, Essex. I would like to invite an experienced astronomy enthusiast to help me with the telescope. 

 

What is your fee for an outcall visit to your customer’s home?

 

[Alex Pratt]

I found the attached photo in Melvyn Taylor’s archive. No details are given, but I think it is a picture of the renowned American observer Walter Scott Houston (1912-1993). Can anyone confirm this?

‘Scotty’, as he was known, was active in many fields of amateur astronomy, and is particularly remembered for his Deep-Sky Wonders column in Sky & Telescope.

In Melvyn’s tribute to Scotty in the 1994 March VSS Circular No. 79, he writes that he met him in 1990 July at the European meeting of the AAVSO in Belgium. Unfortunately, Melvyn’s 1990 Observing Diary doesn’t mention this meeting.

Clear skies,

Alex.

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[Eric Watkins]

Whilst test running a new 2nd main telescope (16″, F:6 Newt)  I was able to image the new Nova in Hercules, using a Moravian MkII 3200ME camera, 2x binning and a 1 sec exposure

[Nick James]

This is the set-up I’m using for the live stream. It is a Megrez 72 FD refractor on a NEQ6 with an IP camera module which feeds video directly into OBS via a long PoE Ethernet cable and then on to Youtube. It’s the first time I’ve tried this and it was far too easy! Hopefully the weather will play ball on Thursday.

[Michael E. Marotta]

Thanks! Like most amateurs, I do a lot observing and not enough reading and studying. I do tell my friends that the stars are pretty at any magnification but if you do not understand what you are looking at, you are missing the essence of the experience. 

I am impressed with your instrumentation, the very fact that you have it. The American Astrnomical Society has (another new) initiative to reach out to its amateur affiliates and – with the purchase of Sky & Telescope – to amateurs in general. The story line is that in the 1920s when professionals were using sophisticated and expensive equipment, amateurs drifted away from the AAS. That may be true. But the fact is that now, just for example, you have basically consumer goods that would have been science fiction 100 years ago. 

I just attended two AAS conferences this year, the 237th General Assembly and the 54th Dynamical Division. There were some interesting papers, but most of what I saw lacked what (if I may) I typify as British empiricism, you know, actually kicking the rock. So, I downloaded your graphs to a folder on my computer for Spectroscopy. 

All of that is to say “thanks” for expanding my understanding.

[Steve Holmes]

A very good point Jeremy, which I put to Roger to ask for his comments. He said that when he discovered the problem with the 6×30 finder (which was simply the one supplied with his telescope rather than a deliberate purchase) he did indeed consider getting a 9×50 but, as he already had the old webcam and other “bits & pieces” from earlier projects, he decided to give the “electronic” option a go first. It was really only when he discovered that the prototype device worked so well, and that it might be able to be manufactured for a price comparable to that of a 9×50, that he began to think about whether it could be commercially produced.

While the webcam finderscope and a 9×50 will have about the same sort of performance (in terms of FoV and sensitivity), the electronic option does have a number of significant advantages over its optical cousin, which I noted in my very first post:-

1) The view seen through an electronic finder can be easily manipulated, both mechanically and by use of the driver program, to align it with that given by whatever star map or program one is using to define the hopping sequence. This includes the ability to “flip” the image in two axes as well as rotate it, something which is impossible to achieve optically without the use of additional lenses or prisms. It should be noted that, as Roger pointed out, the image in an optical finder is inherently “upside down” but the orientation changes if, for example, a diagonal prism is in use, all of which can be confusing for a beginner. The ability to easily alter the image orientation avoids these sorts of issues.

2) An electronic finder provides the observer with a much more convenient “operating environment”. Even a diagonal prism cannot always avoid the need for a most un-natural stance to be adopted in order to look through the eyepiece of a finder. Viewing the scene on a screen removes this problem.

3) Use of a camera enables the observer to take images during the hopping sequence, which can be useful for analysis after the event (particularly if the sequence went astray somewhere) and to document the sequence, perhaps to teach someone else how to carry out the same operation.

4) Driver software could enable the viewed image to be processed “on the fly” in order to improve the image quality and hence the effective sensitivity, which might permit objects at the limit of detectability to be seen.

Roger also noted that he had tried a 9×50 and found that although the performance was indeed a little better than a 6×30 it was not significantly so. While less bright stars could be seen, the difference was small and the FoV was 1 or 2 deg. less than achieved by his device. In addition, the 9×50 was much heavier which required extra weight to be added to the OTA counter-weight in order to maintain its balance.

All the above persuaded Roger that the device he has created would be of considerable benefit to a less-experienced observer, hence his request that I begin this post.

[Colin Hall]

Eric

A heavy mass (telescope) at the end of a cantilevered metal beam will be very prone to low frequency vibration. Your concrete pier will have greater mass and stiffness so it will have a higher fundamental frequency – which is why it does not ‘see’ the road noise. Sand filling will move that frequency higher but you may need a more drastic shift.

Best of luck.

Colin    

[Grant Privett]

I think you will find that the people on here were all beginners once and most did star hopping and remember it well. Some still go that way by choice. I myself didn’t use a GOTO in anger until about 2008 – 37 years since I first had a telescope. While I wanted an LX200 from their introduction onward, mortgages got in the way… An EQ6 eventually proved affordable and is still what I lug outside at night.

My experience suggests that Astrometry.net will generally solve any image with more than 10 stars on with an SNR > 5. I’ve seen lots of frames solve with 8 stars – but it may take longer. So, what size webcam sensor are you thinking of then? In a 1sec exposure with a 100mm aperture (£60 from a car boot sale) with an uncooled Lodestar I would expect to image stars down to 12-13th mag which with the 100mm gave an ~30 arc minute field. So what field of view are we thinking for the webcam? Could you post one of his pictures?

Also, the idea of using the main scope was mainly for simplification ie no need for finder scope and the camera used could be used for object imaging.

If you had an alt-az mount set up roughly level or a German equatorial aligned by eye to the pole star, by recursively taking images and adjusting the scope slow motions (as indicated by software) either in alt/azimuth or RA/Dec – you would move toward the correct position even if the scope was not properly aligned. The better aligned the quicker it would succeed, but it would still work in a few iterations (unless your alignments were hugely out – a spirit level for alt/az and the pole star would avoid that).

The lack of blobbiness might be explained by the colour webcam having an integral IR blocker (quite common) but the cost of that is lower camera sensitivity and fewer stars.

Re: eyeballing. You don’t need to know where the telescope is pointing. If you plate solve, the software will know where its pointing from the plate solution for the middle pixel of the image. Thus it can tell you in which direction to move the slow motions. You just need to move in roughly the right direction.

From where I’m standing – beyond using a guide camera instead of a normal Zoom/Skype webcam – the issue isn’t so much the equipment as the software to use it. Its fairly simple though.

[Steve Holmes]

A really great bit of lateral thinking there Grant, but I feel it doesn’t really move us forward. I’m sure that an 85mm reflector would indeed give a better image than a small refractor finder but the practical difficulties of mounting, and probably counter-weighting, such an item on the OTA of the sort of slightly up-market but still essentially “consumer” reflector a keen beginner is likely to be using (something like a Skywatcher 150?) hardly bear thinking about. Then of course, as the 85mm will almost certainly have been intended to be used as a “proper” (if small!) telescope rather than a finder, there is the question of FoV to consider. One might even have to mount a finder on it!! (and round we go again). As for “blobby coloured images”, I can assure you that those produced by Roger’s device are nicely round and white, right to the edge of the field. [P.S. I sincerely hope you didn’t mean “85mm refractor“, by the way – available, but not exactly at the budget end of the market!]

We did consider using Uranometria as a guide to star hopping, but I’m afraid the Bodleian didn’t seem keen to lend out their copy ….

Moving on to your second post Grant, I knew that Roger had mentioned “plate solving” so I checked back with him and he confirmed that, to put it succinctly, “been there, done that, didn’t get the T-shirt”. There were two basic problems. Firstly, astrometry.net rarely came up with a solution, even “after the event” let alone “live”, probably due to having captured an insufficient number of stars. Then, even if it had found a solution, the instruction to move X in RA and Y in Dec. does rather assume that these axes are correctly aligned and that the relevant setting circles are accurately calibrated and with a fine enough resolution and lack of back-lash to permit an accurate move. With a beginner’s telescope which has to be heaved outside and set up each time an observation is attempted, neither of these constraints is likely to be true. If they were, one could of course simply use the setting circles to point directly at the target of interest without having to go through the star-hopping process. As mentioned earlier, not such a problem with permanent installations but a frequent problem with beginners’ set-ups.

In Roger’s case, the reason he was needing to visually identify exactly where he had got to in the sky after each “slew” between target stars was precisely because he was aware that, although he had taken care to ensure that his equatorial was set up as accurately as possible and that he had turned the dials as precisely as he could, he was aware that the setup was usually just slightly “out” which meant that the end-point was often not quite where it was intended to be. This error could easily be corrected if only he could see sufficient stars to get a “fix” – not possible due to the small FoV of the main instrument and not possible through the optical finder due to low sensitivity. Hence the need for a wide FoV, high sensitivity, “electronic” finder.

And yes, “eyeballing” will certainly give a good starting point but what then? Looking along the tube will give an approximate aiming point but, assuming the target is invisible both to the naked eye and to the (optical) finder, this could be some distance away from the intended aiming point. Even if it’s fairly close, unless you know exactly where the telescope is pointing there is no way to know in which direction to move, let alone how far. As above, relying on the RA & Dec. circles may not be helpful, and “random search” (taking images each time through the main instrument) is unlikely to be effective for faint objects.

I suppose a summary of many of the points I have made in all the posts is “Welcome to the world of the beginner”! Everyone has to start somewhere, and that somewhere can be well down the scale of instrument sophistication. Beginners often have problems which “professional amateurs” don’t even think of, which can lead to blindness as to reasonable ways to solve those problems.

[Grant Privett]

I’ve just realised I missed something in this.

Why not put the camera straight on to the main telescope, display the image it generates, platesolve via a cygwin installation of Astrometry.net and have the software tell you how far to move in RA and Dec to get to the right place. Most Astrometry.net solutions only take 10secs on my 5 year old laptop, so you could point at the rough location and be there 2-3 minutes later.

If you are not autoguiding why have the finder guidescope at all? Eyeballing along the tube would give a good start point. 

[Andy Wilson]

A few years ago I got the equivalent 50mm guide scope and camera, currently selling for £235 on this page. I think it was more expensive when I bought it and prices have come down. They do various options, including the telescope guider body with a non-rotating helical focuser on which you could put your own camera of choice for £109.

https://www.altairastro.com/guide-scopes-97-c.asp

Of course the main purpose of this setup is as a guide camera rather than a digital finder, but I found it worked perfectly for my purpose. A GoTo mount that wasn’t quite good enough to always put the target in the small field of view of the guide camera on a spectrograph.

Best wishes,

Andy

[Steve Holmes]

Thanks for those comments. However, between them they do rather illustrate the problems with “standard” solutions which my friend Roger was trying to solve. In the case of the Evoguide 50ED plus ZWO camera bundle, the most obvious objection is cost! (£319, even as a “special offer”). While I’m sure there must be a market for such a device at this price point among “professional amateurs”, I rather doubt whether many casual backgarden skywatchers would be willing to invest this amount, possibly more than their entire setup has cost them so far, in order to obtain one. This is further compounded by the fact that this device does not seem to be able to make up its mind as to what it is. For example, a “webcam finderscope” does not need the ability to accept different cameras/eyepieces nor does it need to be able to alter the focus: once the selected webcam is in the correct position it should not need to be altered or adjusted thereafter. Also, does a finder for a “moderate” telescope really need a 50mm “Ohara ED doublet objective that includes an S-FPL53 ED glass element”? All these additions can only serve to increase the price. The fact that this item does not seem to be intended purely as a finder is to some extent borne out by the reviews, which refer to its use as a astrophotography camera in its own right. Irony of ironies, one review even mentions the need for a finder to be mounted on it! Which brings me to the next disadvantage of both the Evoguide setup and adapter rings – limited field-of-view.

The FirstLightOptics page for just the guider has an “applet” for determining the FoV of various setups, which shows that the Evo plus ZWO camera bundle can span from M32 to M110 – barely 1 degree. This again would tend to confirm that it is not really suitable purely as a finder for a moderate OTA. Adapter rings tend to have the same problem: Roger’s setup can achieve an FoV of over 6 degrees, which is much more usable for star hopping. Finally, although Robin’s setup is much nearer to Roger’s, he himself says that the webcam he used is not sufficiently sensitive, thus emphasising the need for careful selection of components.

In summary then, although there are products out there which address the same “operational space”, there does not seem to be anything currently on the market which combines high sensitivity, very wide fov, and modest cost – unless someone knows differently, that is!

[Eric Watkins]

Evening,

I have just test driven a new set up, an original ME mount which supports a 16″ Newtonian reflector.  This system is mounted on top of a 1m tall  fined steel pier which is in turn bolted to a concrete block 1m and 0.75m square  below the ground surface.  I find that there is some induced road traffic vibration from a road some 35 m.   I also have a 14″ sct on an ME II mounted on a similar sized concrete block, but with a cast concrete pier and situated 40m away from the same road which  I have used for many years with no such problem.   Both ‘scopes are used for CCD imaging and photometry.

I  plan to remove the steel pier and replace it with a 1m tall concrete pier cast onto the existing concrete block.  Further  I will

place the telescope mount plate onto 4 vibration pads made of rubber or sorbothane similar to examples attached . 

I would be interested to know if others have  had a similar problem, tried similar solutions and how they got on

 Best wishes,

Eric

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[Steve Holmes]

I have been giving some help to a former school-friend who has fairly recently taken up observational astronomy. One of his major problems has been star hopping. He prefers to locate a target manually, rather than by GOTO methods, but has been frequently thwarted by the numerous difficulties encountered. A significant one of these has been an inability to accurately determine exactly which starfield he is looking at because of the limited light-gathering capacity of his finder. This has required him to take images using a webcam with his main OTA and (hopefully!) use these to determine his viewpoint, but his ability to do so is severely constrained by the limited field-of-view of this setup.

Being a practical person, he has developed what seems to be a simple yet inventive solution, which can best be described as a Finderscope Webcam. In other words, a webcam mounted on a finder, imaging the scene afocally. This has the double advantage of greater sensitivity while retaining the wider field-of-view. Whilst currently a rather “DIY” device, it uses easily available components combined in a rather novel arrangement and so should not be difficult to replicate.

I have seen promising results from it and so feel a device such as this could be of value to other observers, as it does have a number of additional advantages over a standard “optical” finder:-

1) The device can be rotated (manually) and the image flipped (using the driver program) so that the view given by the webcam finder matches any “planetarium program” view that the observer might be using to verify that the hopping sequence is being carried out correctly
2) The “ergonomics” of the device are much superior to that of an optical finder. Specifically, because the observer does not have to look through the device there is no need to adopt uncomfortable postures at the telescope and no problems are caused for spectacle wearers
3) The observer can record both the hopping sequence taken and images of interest found during the “hop”, both for later analysis
4) By use of suitable driver software, it would seem possible to apply “dark frame correction” and live stacking to the image stream. Both of these techniques would significantly increase the image quality compared to an optical finder

I was thus wondering if any member knows whether a similar device is already available or has contacts with manufacturers of telescope accessories who might be interested in developing & marketing such a device?

[Mike Harlow]

An image from 23:30UT last night (10th)…nova at centre of 25 x 25 arc minute frame, north up. It may seem like overkill to image a mag 5.3 nova with a 30cm telescope (!) but I’ll be able to follow it as it fades back to mag 18,19 or less with the same set-up.  Should make a nice sequence…maybe even an animation…!?

I did look but couldn’t see it naked-eye. But it was very nice through binoculars and the 4 inch F/5 finderscope on the main telescope. 

Mike.

[Jeremy Shears]

I’ve just posted an article about observing this dwarf nova. This is a star that is always doing something. It has outbursts every 11 days or so, and yet has been neglected of late.

It’s also a good target for those wanting to have a go at digital photometry. For several years I used a 10 cm refactor and CCD to follow this object. And you don’t need to use a filter. Perhaps you can fit in a few 60 sec exposures among your other imaging projects.

Visual obs also welcome, although at it’s brightest it’s 15th mag, so a large telescope will be needed.

[Alex Pratt]

Test-Bed Telescopes and Flyeye – monitoring the skies for Near Earth Objects

ESA – New ESA telescope in South America to search for asteroids

New telescope at ESO’s La Silla joins effort to protect Earth from risky asteroids | ESO

Alex.