Search Results for 'espin telescope'

[William Bristow]

Hi Nick.

If you want an independent low power 12v rain monitor with switched output for the dome controller take a look at the Hydreon RG-11. I have one as a belt-and-braces backup for the AAG. The RG-11‘s switched output is wired in parallel to the AAG so either unit will cause Pulsar’s Rigel controller to close the shutter.

The RG-11 uses IR to detect rain droplets on a transparent dome, same as automatic windscreen wiper control in cars. It does have an internal heater to help evaporate condensation and works in a different way to a capacitive or resistive water sensor by reacting to sudden changes in reflected IR on the clear dome to trigger the relay so even if static water droplets are on the dome as long as no further droplets are seen then it will open the relay much earlier than the AAG unit.

http://www.weatherstations.co.uk/hydreon.htm

My experience so far is that cloud detection is more important than direct water droplet monitoring to prevent the optical equipment from rain damage since the sensing area of capacitive/resistive/optical rain sensors is rather small, the telescope can get quite wet before a single droplet is detected by rain detectors, I consider these to be fall-back safety backup devices rather than a primary controller.

I have mixed feelings about ACP as the observatory control software and was using CCD Commander for a while. Having a Paramount I am tied to having the TheSkyX running and ACP won’t work directly with TheSkyX’s automation interface. ACP requires Maxim and Focusmax so I have four separate applications running that often require updates to adapt to changes to Windows OS.

The only function in ACP that made it attractive was the scheduler engine. With our UK weather, being able to ask ACP to image a target automatically and keep acquiring data at the best times, however many nights / weeks / months that might need until all requested data had been captured, was the ‘killer’ application.

Software Bisque have been dropping hints that they are developing a new version of Orchestrate for TheSkyX that would offer many of ACP’s fuctions for the last four years or so but so far no news of progress or a release date and I couldn’t wait any longer so am committed to ACP, Maxim and Focusmax for some time to come. Certainly keeps you poor this hobby!

Regards.

William.

[Andy Wilson]

Hi Jack,

I’ve seen both of what you describe.

I found that depending of the angle of the spectrograph due to gravity, then there can be small wavelength shifts. Nothing to cause a serious problem during normal observing, though on a run lasting over an hour might then the overall resolution could be slightly reduced. The tests I did were about 3 years ago and I’m not sure I’ve still got a copy. With the spectrograph off the telescope I took neon calibration images with the spectrograph on each side and vertical, to observe the most extreme effects. I then made careful measurements of the centres of the neon lines at the same position on each image.

It might be worth making sure all the screws in the body of the LHIRES III are tight, but I think small shifts are to be expected. There is more than one moving part and heavy cameras attached. Only a minute flexure will cause a small shift in wavelength. That is one reason why fibre fed spectrographs can be more stable, though using optical fibres introduces a different set of problems.

I also see shifts in focus with temperature. So on a cold night if I start with the neon lines in perfect focus then often they won’t be in perfect focus at the end of the run. This is again something I live with. The flat fields will be slightly compromised, but if I refocus then that would also compromise the flat fields. Of course as long as you retake the flats after each refocus then that is not a problem. This is the same behaviour as needing to refocus a telescope due to thermal contraction from falling temperatures.

Best wishes,

Andy

[Grant Privett]

As I am in the process of planning a new observatory (probably a roll off shed) for our new home, I am looking at options for control of the scope. I had wondered about logging in remotely to a laptop left by the telescope to control it, but recently saw there are ethernet adaptors made by Startech that allow 4 USB sockets to be accessed directly via a Cat5/6 cable – perhaps as much as 100m long.

Now, that would save me a lot of palaver in that I could have the CCD, an autoguiding camera and mount all controlled down the same cable with perhaps enough capacity left over for an all sky camera, or more likely, an electronic focuser. 

Looking at the Amazon feedback I see mention that others have done this, so I wondered if anyone had a story to tell on this. Does it work seamlessly with imaging or do we end up with the USB connections interfering with each other and messing things up – I recall using USBs on a laptop where moving the USB mouse impacted the signal from a USB record turntable.

Thoughts anyone?

[Nick James]

If I remember correctly Gary Poyner had a heater like that in his telescope and came out one day to find that it had caught fire and melted his telescope tube. I’m sure it worked well at stopping condensation though…

[Peter Carson]

Hi Lars,

The forced ventilation kit will help move the air around and reduce condensation in humid weather. It will also help flush out warm air after hot days so your telescope will reach night time temperatures more quickly.

However I find I get the most condesation problems when the mount and telescope have been cold for a long period, say after a prolonged period of cold weather, then the weather suddenly warms up. The warmer air carries more miosture and this condenses on the cold metal surfaces and even the optical surfaces. Additional ventilation at this point only makes things worse by supplying more moisture laden air to condense on the cold surfaces. Heat or dehumidification is the only way to resolve this situation. I said in an earlier post that I previously used small tubular heaters to reduce the condensation issues but have recently reverted to dehumidification which works perfectly and for a cost lower that the ventilation kit in your link.

Peter Carson

[Lars Lindhard]

My old roll-off observatory is a bit worn and it might be time to replace it with something else.  A Pulsar dome seems to be a possibility – although rather expensive – but I fear that moisture might be a problem, as I can read that some of you have to deal with moisture in your domes.

I don’t want to place my telescope inside a wet “tin can”.

Pulsar has made this gadget

https://www.bresser.de/en/Astronomy/Domes/PULSAR-Ventilation-System-for-Observatorium.html

Do you think that this could help?

Regards
Lars

[Nick James]

Here’s an image of it from a few minutes ago. The telescope wasn’t tracking very well and the SN is very close to the centre of the galaxy but you can see it.

[Peter Meadows]

Hi JR,

Firstly I assume you have successfully using the PST visually with an eyepiece to see the chromosphere – although solar activity has reduced recently there is a reasonable group at the moment which even produced a flare this afternoon. So if all is OK using the PST visually this indicates that you have correctly wavelength tuned the telescope.  If it off-band you will just see a featureless disk a bit like in your image.

The difficult part of using a DSLR or indeed any other type of camera with a PST is obtaining focus. This requires using a Barlow lens (which you appear to be using) or an eyepiece lens to bring the focal plane of the DSLR closer to the PST eyepiece holder.  I suggest you perform a Google search using ‘PST and DSLR’ without the quotes.  There you will find videos and other information (e.g. https://www.youtube.com/watch?v=RYDzdYkVbGM).  Note there is no need to modify the PST eyepiece holder itself.

Peter

[Stewart Moore]

My observatory is 9ft 6in x 9ft 6in and I certainly wouldn’t want it any smaller.  If I was building again I’d make it 10ft x 10ft.  But then I’m a visual observer who needs to walk around the telescope and climb up step ladders etc. I’m pleased I made it very substantial. It is bolted to the base by studs cast into the concrete – essential when you live close to the windy east coast. It also has a damp proof membrane to protect the wood

[Alan Dowdell]

Sad to read the passing of John. For me he was one of the associations greats. He  was for so many years at Winchester Weekends the star of the show. Each year we looked forward to hear about the next great telescope he was making.I also have great memories of visiting his house and workshops some years ago. To some it would be a scrap yard , to John anything could be turned into a telescope.I am proud owner of a very early focusing mount which I keep in pride of place at home. I will raise a glass to him at the next Winchester.

[Eric Watkins]

Grant,

I still have a 13′ x x12′ roll of roof observatory with such a roof.  I used well painted hardboard sheets nailed to timber for the walls.  It’s still standing and was used for over 20 years and fell into some disrepair as a result of long standing serious illness.

I did find that during the summer the interior got very warm and equipment took some time to cool down.  Condensation was never a problem.

I now have 2.7 metre dome on top of a wooden construction for which the dome and metal work (including telescope) suffer from condensation for which I use de-humidifiers that solve the problem.

Regards,

Eric

[Stewart Moore]

Grant, I’ve had a wooden run off roof observatory for around 12 years.  The walls are tongue and groove and the roof is ply covered in roofing felt.  It runs on steel angle rails with B&Q plastic wheels.  The roof is ventilated around the roof line.  It has been totally water proof with no condensation whatsoever – an advantage of wood – and the telescope tube never has condensation on it.  The only problem is that it is so dry it gets taken over by spiders.  Ladybirds also like to over winter in it.  Another advantage of wood is that it’s easy to screw boards etc. to it and fix electric cables.

[Paul G. Abel]

Hi John,

In the past I was able to make it out easily in a 4 inch telescope. In the last few years, I have seen it without too much difficulty in a 90mm refractor. The use of a W#80 (light blue) helps to make it easier to see.

Cheers,

-Paul

[Neil Morrison]

Good evening Dominic.I have been using  a Sky Watcher  Star Adventurer   over the last 12 months or so. I have used it to carry  a 500mm f5.5  Telescope  and seems to  track  well . As commented  already the attachment  screw to the Tripod should  be very very tight.    With the  poor weather  last year not very  much photography was  undertaken  let us hope for  better in 2018.

Regards

Neil

[Dominic Ford]

Browsing the shops, I’ve noticed that AstroTrac DSLR mounts have become quite hard to come by lately, though some shops like Rother Valley still claim to have them in stock. I suspect AstroTrac have stopped making them, since their own website says “out of stock”.

In its place, Telescope House are now selling a couple of other models — the Vixen Polarie Star Tracker, and the iOptron Skytracker Pro.

Has anyone tried either of these mounts? On paper at least, the iOptron looks like the sturdier of the two.

[Nick James]

I have just heard from Crayford Manor House Astronomical Society that John Wall died on Saturday.

For those that don’t know, John was the inventor of the Crayford focuser along with many other things astronomical. He also built a 30-inch, f/12 refractor at his home in Dartford using the lights on the Queen Elizabeth bridge to demonstrate its optics. John also built the 24-inch telescope that CMHAS had installed at the Manor House until they left to move to their new location a few years ago. That is now at the Lime Tree Observatory near York.

I was lucky enough to know John when he was at Crayford and as Papers Secretary I would receive papers from him describing large (and possibly slightly impractical) telescopes some of which actually got built. John definitely didn’t do conventional!

[Peter Carson]

Hi Nick,

For many years I used to run two small 60w tubular heaters located close to the mount and telescope which was covered with a large cotton sheet “tent”. The heaters where controlled by a time switch that put them on for a few hours generally before dawn when the equipment was at its coldest. This worked well in most situations. However in the late autumn when weather conditions can change rapidly between near freezing temperatures to a mild south westerly maritime airstream I still occasionally suffered condensation problems.

Last summer I reduced the ventilation in the dome and installed a desiccant type dehumidifier which I run manually for a couple of hours on occasions when I think the conditions are likely to produce condensation or after I’ve shut the observatory up following an observing run.

Since installing the dehumidifier I’ve not noticed any condensation problems even during weather conditions that would have previously been an issue.

It’s important to purchase a desiccant based dehumidifier as the refrigerant types do not work at cold temperatures. The dehumidifier need not be large and can easily be purchased from most domestic appliance suppliers.

Peter

[Mr Jack Martin]

Andy,

Which flip mirror were you using on your telescope ?

Regards,

Jack

Essex UK

[Andy Wilson]

Hi Alun,

That is a nice bit of remote control for your neon and flat field lamps. I did give it a bit of consideration, but found I don’t really need it at present. I am at the telescope when I change target, and everything is sufficiently solid that nothing moves when I flick the switches on the spectrograph. This would be great for remote observing!

Andy

[Andy Wilson]

Hi Ron,

I also own a 10″ Altair Astro (GSO) RC. I understand that Altair made some kind of modification to the GSO RCs before selling them. I think it was something to do with the mirror cell but I don’t know exactly what. They have stopped selling them now.

I’ve done collimation once and it was a bit of an ordeal. I expect it is one of those things that once you have done it a few times then it gets much easier. I’ve found it to be very stable and appears to hold collimation well. Though as I am also using it for spectroscopy, I don’t worry too much about having the collimation absolutely spot on as this won’t affect the spectrograph resolution, just the throughput and so SNR.

I also upgraded to the Feathertouch Focuser and found it to be rock solid. I’ve not bothered with a motorised focus as I am in the observatory and I can tweak the focus if needed. Though I find the whole telescope and focuser to be extremely stable and so I rarely need to adjust it, except due to seasonal temperature changes.

If you get a 16″ then I’ll be very interested to hear how you get on with it. I wonder about one day upgrading to a larger GSO RC. Though for me the choice was also about a compromise between matching the focal ratio with my LHIRES III spectrograph, and keeping the focal length short so that I have a reasonable field of view in the guide camera.

Best wishes,

Andy