Search Results for 'espin telescope'

[Andrew Read]

Hello,

I’m about to order a custom-made permanent pier and need to specify the desired height.  The pier will be for an open roof-top observatory, and on top I’ll place my iOptron AlzAz goto mount and 90mm f5.6 refractor.  Visual observing only, from 30 degrees to the zenith.  I have a small stool for observing, but it’s inexpensive and could be replaced.

Clearly the eyepiece will be at a different height depending on the altitude of the target, and it’s not impossible I might own another telescope at some point, so there is no one right answer.  But I would be grateful to hear of any comments from experience with this kind of trade-off decision!

Many thanks,

Andrew

[William Bristow]

Jeremy.

Forgot to mention earlier, while setting up the new laptop and testing cameras etc make sure that you don’t place loops or coils of excess USB cable and power cables close to the laptop.

Camera should be as far away as it would be when attached to the telescope and the USB cable should be laid out straight, same applies to the camera power cable. Avoid running USB cables parallel to the laptop chassis, cables should always be run outwards from the laptop where possible to avoid induced interference.

William.

[Edward Fraser]

We are an Astronomical club offering observing opportunity’s to the general public once a month and because these sessions are now getting very popular we are looking into ways we can accommodate the many people who want to have a peek through our instruments.  One of the thoughts were that we replace the telescope eyepiece with a camera and connect it remotely, or by wire, to a monitor or computer screen indoors such that many people, wheelchair users and the less infirm can view what the telescope is focused on. 

Has anyone got any experience of such a setup with advice on how it could be done?

The telescopes used for our outreach sessions are a Celestron 11GPS SCT, 8″ Newtonian, 8″ SCT, Refractors from 60mm – 120mm.

Cheers

Ed

[Robin Leadbeater]

The paper “The Zwicky Transient Facility Census of the Local Universe I: Systematic search for Calcium rich gap transients reveal three related spectroscopic sub-classes”

Kishalay De et al

https://arxiv.org/abs/2004.09029

has been accepted for publication. It includes a spectrum of SN 2018gwo taken with the modified ALPY200.

It was discovered by amateur Patrick Wiggins and I initially classified it spectroscopically as a type 1c supernova.  It turned out to be a rather rare Calcium rich gap transient supernova, based on a spectrum taken in the nebula phase 5 months later using the Keck 1 telescope. (One of only 8 out of 754 supernovae found during the survey period) so I am included as a co-author. ZTF use a spectrograph with a similar low resolution to the ALPY 200 (R~150) to classify transients they find but the system was down for maintenance at the time. But for the amateur discovery and initial classification of SN 2018gwo, it might have been missed.

Cheers

Robin

[Alan Thomas]

I tuned in yesterday and found this a very interesting presentation, giving lively and sometimes humorous insights into how professional astronomers spend their time. I hadn’t heard the one about the telescope with bullet holes in the mirror!

It seems there are only about 50,000 astronomers on the planet, so we are a comparatively rare breed. Will amateur astronomers be The Last Stargazers, given that the pros rarely, if ever, peer into an eyepiece?

Well worth catching this if you missed it last night.

Thanks for posting, Andy.

[Tony Marlow]

I am clearing out my loft prior to moving house and have a several books and some optics and telescope parts that might be of interest to someone.  The books were purchased in the 1960’s and 70’s and are in reasonable condition, most being first editions.  The optics include a 254mm f/7 parabolic mirror by Wildey complete with a 61mm minor axis flat and spider, also by Wildey, and a 160mm f/8 mirror and flat, and other bits and pieces as well.

Lists of the books and optics are attached.

I will consider a reasonable offer for the Wildey 254mm mirror and spider/flat, but the others are free.  Collect or pay postage please.

Please email me on tmarlow97@gmail.com for photographs of the optics etc.

Tony Marlow

Ruislip, Middlesex.

Attachments:

1. Astronomical-equipment-list.docx
2. Astronomical-book-list-ver3.docx

[John O’Neill]

Hi Lee,

My understanding of preceding/following is that it only refers to celestial west/east respectively. This is independent  of any rotation of the planet.

If you turn off the power on a telescope drive, a planet will drift in the Field of View in the preceding direction.

John

[Richard Miles]

Thanks Andrew for considering others sharing this initiative.

Like you say, once you go into the nitty-gritty details, it becomes more complicated especially the more people involved!

Kevin Hills has recently been out at the site on La Palma troubleshooting dome problems for instance. FYI: The subject has come up several times at the ‘BAA’ but has never gathered a sufficient head of steam to properly start the train moving along the tracks.

[Stewart John Bean]

Hi, Just  found this thread and wondered the current status?

I use the itelescope network and might consider joining a BAA group

Stewart

[David Strange]

David, we can offer to live stream from the Lockyer telescope (6.25″) – the one that Lockyer used to discover Helium on the Sun. We have a good broadband connection at NLO.

David

[David Arditti]

I’m helping the RAS and NAW committee organise live streaming of Mars as seen through telescopes during National Astronomy Week, which will be 14-22 November. We are looking for individuals, observatories or local societies who could take part in this by operating one of the streaming stations on some evenings of that week. We’d like a spread of stations around the country, or even some abroad. Further explanation and guidance will be given, but the equipment needed will be a driven telescope, suitable camera and computer, and good internet connection at the observing site. Please contact me if you would be able to help.

David Arditti

Director, Equipment & Techniques Section

[Jeremy Shears]

According to ATel 13904, the 12.9mag (unfiltered with V zero-point) optical transient TCP J00114297+6611190 was identified on 2020-07-27.9302 UT by S. & K. Korotkiy and spectroscopically confirmed as a Fe II type classical nova on 2020-07-29.025 with the 2.5m Sternberg Astronomical Institute telescope by the team of Kirill Sokolovsky.

Nova Cas 2020 has coordinates (J2000.0): R.A. 00 11 42.96 Decl. +66 11 20.8

Observations and spectroscopy urgently required. An AAVSO chart and sequence are available.

[Robin Leadbeater]

The mirror slit does have a couple of drawbacks too though. Bright stars are normally guided when on the slit using the overspill. (Typically the slit width is chosen to match the star FWHM so there is always some light which does not pass through the slit) The resulting image is “Hamburger” shaped though, split by the slit, which some guider programs struggle with. Also because unlike an air slit, the light has to pass through glass this can limit measurements at the UV end of the spectrum. (The beam spliiter has the same problem though.)  The original not for profit LHIRES kit had jaws lovingly hand polished by volunteers but that would be expensive to do commercially.  Christian Buil has been experimenting with reflective air slits (from the base ALPY module) for the UVEX, along with using all reflective telescope optics and a different glass for the camera window to reach a remarkable 3200 Angstroms. Beyond that atmospheric ozone absorption becomes an issue.

http://www.spectro-aras.com/forum/viewtopic.php?f=45&t=2277&start=10#p12459

Cheers

Robin

[Robin Leadbeater]

I don’t believe the lack of  remotely operating spectrographs is necessarily due mainly to the lack of suitable instruments. There are spectrographs such as the ALPY and DADOS which need no adjustment (In fact the SX spectrograph should not need adjustment in normal use with a suitable size camera really) and others like the Eshel which is capable of fully remote operation but you see very few operated this way. Remote operation of slit/fibre fed spectrographs is much  tougher than imaging, particularly if you want to automatically acquire targets. (Andrew will be able to advise on that)  Spectroscopy also needs a lot of  telescope time which is expensive on rented telescopes. 

Cheers

Robin

[Andy Wilson]

Thanks for sharing this Callum. I heard of this spectrograph a few years ago but didn’t know they were adding automation.

It is great that SX are entering this field though I didn’t see anything that tells me how well the spectrograph performs. The idea looks great, but they really need it in the hands of someone who knows how to produce good quality spectra to see how well it performs in the real world. It could be fantastic but they only showed the most simple of results, a bit like demonstrating a new telescope by taking single images of the Moon without proper processing.

I would want to know how stable is it on the back of a telescope in an imaging run. It appears the design should be very stable but theory and practice don’t always match. I also want to know what the resolution is as that defines what you could use it for, along with how that matches to CCD pixel size. Interesting that the camera can be shifted across the spectrum though I’d want to know how much of a spectrum you can fit in a single exposure, and how stable that movement is. It has to be absolutely rock solid, otherwise things like wavelength calibration and response correction needed to create good quality spectra would fail. If someone could obtain spectra of more challenging targets and do the full end to end process including response correction that would go a long way to demonstrating they have a high quality product.

I do not agree that they are coming in cheaper than their competitors. There are only a couple of modular spectrographs I can think of, most come as complete units. Of the modular spectrographs one is cheaper and the more expensive one is a top end spectrograph designed for large research telescopes. They appear to be coming it at about the same price or possibly more expensive than complete unit spectrographs. That is not to put their spectrograph down, just I did not agree with their comments on the price. This might not be a negative as they have automation, though they are not the only spectrograph with automation capability.

I don’t mean to be too negative as I think SX produce great CCDs and accessories, and I want this to be a great spectrograph. I am just hesitant as this is their first foray into spectroscopy and I’ve not seen any results that demonstrate the quality of the spectra it produces.

Cheers,

Andy

[David Swan]

A fascinating object. Friends and passers-by have been out for a look and have been most impressed. I have found that non-regular stargazers, with just help to point them in the right direction, are able to pick it up with the naked eye and notice the fuzziness reaching upwards. Most people favour the view through binoculars (10 x 50s) rather than the telescope (200mm SCT, 32mm Plossl). I am pleased to have been able to pick up the ion tail with just single frames with a DSLR! A greenish tint is also appearing in the coma, as highlighted by Nick James in a recent email.

[Dr Paul Leyland]

Roger has put together an excellent issue, well worth reading even if you do not plan to do any active observing of exoplanets. That said …

One of the links in Infinite Worlds is https://arxiv.org/abs/2003.09046 which points to a paper entitled Telescopes Operated by Citizen Scientists for Transiting Exoplanet Follow-up where the BAA gets a name check. The exciting take-home message from this paper is that amateurs can perform genuinely important original research and save professional astronomers, using both ground-based and satellite facilities, quite literally years of their scarce and expensive telescope time. Even better, telescopes with apertures of 15cm or so are easily capable of contributing to this effort. (Bigger ones can do more, of course, but they are not essential.)

I urge all BAA members capable of imaging the sky to seriously consider spending a portion of their observing time to help out. The efforts need not be full-time as even a few sporadic sessions form a valuable contribution.

Unfortunately the PDF of that paper is just a little too big to attach to this post uncompressed, and the forum doesn’t allow for files with extensions such as “.z” or “.zip”. Accordingly, I created a ZIP file which squeaks under the limit and renamed it with a .fits extension. If you wish to read the paper, please download the file, then rename it to be named “smallscope_exoplanet.pdf.zip” and finally unzip it with whatever archive program you generally use.

[Andy Wilson]

Hi Jack,

I hope you don’t mind but I thought I’d ask what problem it is you are trying to solve.

I remember you were having issues with wavelength shift in your spectrograph. If this is the problem then I don’t think mirror flop in the telescope is likely to be the cause.

Of course if you are having trouble with shifting position of the star when you cross the meridian then that would be fixed by solving mirror flop.

Cheers,

Andy

[David Arditti]

The bolts that are supplied with the telescope are about 2″ long, smooth-shanked and threaded with a ¼” Whitworth thread in the top ½”.

They work by the thread engaging with the mirror cell while the unthreaded section passes through the hole in the back of the scope and the knob clamps tight. Owing the varying mirror position at different focus points, I am not sure if they would succeed in in locking the mirror at any point in its focus range, or not.

Assuming they do, and assuming you are using one optical configuration with camera at a fixed distance out in a Crayford or similar focuser, I don’t see why you should not lock the mirror in position with these screws after you have established the approximate focus point for the mirror, with the Crayford in the middle of its range, to give a bit of temperature compensation around that point. However, I have not tried this. I tend to do my critical work around the same part of the sky, the meridian, so the collimation does not change much.

[Dr Paul Leyland]

It’s not the size that is important, it’s how you use it.

You can do accurate photometry with telescopes of almost any aperture. The only thing that increased aperture buys you is a fainter limiting magnitude for a given exposure time.

People do precision photometry with nothing more than a DSLR and a standard lens. It is rare for the aperture of such a system to exceed 50mm, or half that of your telescope.