Search Results for 'espin telescope'

[Mr Nicholas John Atkinson]

Hi kevin,

I use Maxim dl 6 where there is an option after calibration to guide on all the stars in the field rather than just the guide star. At one time I used PHD with but have found it much easier and more reliable. The other advantage is the point telescope here command. I have ASCOM pointing to The SkyX and Maxim links into this. I have T point add on which will allow very accurate polar alignment but also will correct any pointing errors giving a high degree of confidence. The other advantage of Maxim is the ability to use 2 cameras. I expect with the £/$ exchange rate this will be more expensive but is worth avoiding the frustration of spending hours centering the star.

Cheers

Nick

[Gary Poyner]

Can’t believe it’s been a year since we last did this…

2015 numbers in brackets

Clear Nights (50% or less cloud) 33 (24)

Partially Clear (50% or more cloud)  62 (80)

Total 95 observable nights (104) with 37 of these nights under Moonlight.

I missed 10 nights due to various reasons.

On 40 occasions the BBC weather forecast for cloud cover was incorrect.

Total hours at telescope 223.33 hours (206.88h)

Best month August with 13 nights – 10 clear and 3 partially clear (June 16)

Worst month June with 2 nights – 0 clear and 2 partially clear (Dec 4)

Total visual Variable Star observations 8,022 (7,741).  Only 598 single CCD observations made this year.  This is due to the demise of the BRT and a lengthy Monsoon in the SW of the USA where my AAVSOnet instruments are based.

Happy New year to everyone

Gary

[Denis Buczynski]

The Comet Section is now receiving reports and images of this famous comet.We encourage observers to follow this object and report thier observations to the Comet Section

A description of its prospects written by Martin Mobberley is as follows:

The year 2017 could start quite favorably for comet observers if comet 45P/Honda-Mrkos-Pajdusakova lives up to expectations. This regular visitor is heading north and will just have passed perihelion as January begins. It will be painfully low (but a bright magnitude 6) and immersed in the evening UK twilight early in January, but finally rises to a respectable altitude in the morning sky by early February, moving rapidly north and west through Aquila, the north-eastern corner of Ophiuchus, Hercules, Corona Borealis, Boötes, Canes Venatici, Coma Berenices and finally entering Leo, all in the month of February. The magnitude will drop from around 7 to 11 during the month. The reason for the rapid movement of 45P, is the proximity of the comet to the Earth. It is closest, at a mere 0.08426 AU, on Feb 11.26, while in Hercules. The comet will be moving at 22 arc-seconds per minute at that time. 45P comes close to the Earth quite regularly and made 11 close approaches to the Earth in the 20th century alone. The reason for this is its short orbital period of precisely five and a quarter years, as well as its small orbital inclination of just over four degrees. Unfortunately the Moon will be Full on February 11, the day of closest approach.

A recent image from Gerald Rhemann observing in the pristine skies of Namibia shows the comet is well developed and is showing significant tail and coma features.

Denis Buczynski Secretary BAA Comet Section

Object: Comet 45P/Honda-Mrkos-Pajdusakova Date: 17 12 2016 UT 18h50m Location: Farm Tivoli, Namibia/SW-Africa Telescope: ASA Astrograph 12″f3.6 Camera: FLI ML 16200 Mount: ASA DDM85 Exposure time: LRGB 12/3/3/3 min. Copyright Gerald Rhemann

Attachments:

1. 

   45P_20161217_1850_grhemann.jpg
   

[Gordon Mackie]

Interesting details Denis.

I stayed in this hotel a few months ago and the hotel manager gave a brief of the observatory one evening. I didn’t know it was there until spotting it on arrival, so it turned out to be a nice bonus to the few days in the area. Attached are a few images showing info about the telescope displayed in the hotel. It looks similar to what you posted Denis, but also has some different info (I notice Dave Gavine gets a mention).

I’ve also attached an image of a rather nice sundial that is located above the entrance to the hotel.

[Andy Wilson]

I did once have condensation forming on my CCD coverslip. This can happen with some CCDs when they are kept in a damp environment.

I now place a silicon desiccant bag in my telescope tube when I’m not using it, which I replace and reactivate every so often. I’ve not had any problems since doing this.

Andy

[Robin Leadbeater]

Hi Kate,

I found my Gert Neumann panel and put it in front of the ALPY 600 spectrograph with an ATIK 428 camera. Here is the comparison between the EL panel and the internal ALPY lamp.

 (This is effectively the output from the light source x the response of the grating and CCD camera)

As claimed by the supplier, the spectrum of the EL panel  is smooth with no obvious lines (The small scale ripples in both spectra are from the camera QE and demonstrates one of  the reasons why flat correction is important).

The EL panel could potentially be used as a flat light source for spectroscopy, even though the spectrum shape is very different from the Incandescent Halogen lamp black body curve but unfortunately there is no light from it below 4000A. (The internal Halogen lamp in the ALPY also struggles in this region but in practise it still gives enough output down to ~3600A provided a large number of flat exposures are combined to reduce the noise)

A key difference between imaging and spectroscopic flats is that it is much less important that the field is evenly illuminated since you are only sampling a small slice of the field. Even some variation in illumination along the slit is not important if you are measuring at one position eg as for a star. This means even a crude flat illumination setup can be used. I bought my ALPY before the calibration module came out and used the same flat lamp setup as I used for my LHIRES – A halogen lamp waved a couple of metres in front of the telescope aperture which was covered by a diffuser (actually a pillow case!), similar to Christian Buil’s setup here

http://www.astrosurf.com/buil/isis/guide_alpy/tuto_en.htm

This worked well and I saw no difference when I eventually got the calibration module

Cheers

Robin

EDITED: to mention the grating response

[Eric Watkins]

It would be nice to have regular publication that either lifted the level of “expertise/difficulty” or included more sophisticated  articles. The level of a great deal  of much  amateur work  is on a par with some of the lesser funded, smaller university projects.

I have subscribed to a number of monthly popular astronomy magazines and find that I skim read through them once and rarely return for further reading.    I’ve stopped taking Sky and Telescope recently and should have done so some years ago.

[James Screech]

I would go for a EW type as they are continually changing in brightness and generally have short periods. Possibly VW Cep (mag. 7.2) if you are using a camera lens, this has a period of just 6h 40m so a full orbit can be captured in one night, it is also circumpolar from the UK so can be imaged any time of the year. Or possibly NR Cam (mag 10.76) if you are using a telescope for similar reasons, circumpolar, period 6h 8m.

What camera, lens/telescope are you using?

Before you take a time series in anger you will need to determine the exposure/iso you need for different magnitude stars, making sure you allow some spare space at the top end to take account of non-linearity in the camera, different star colours and atmospheric transparency.

James

[Robin Leadbeater]

Hi Tony,

See  https://britastro.org/comment/2420#comment-2420 for a comparison of two different setups

Dont worry too much about matching and focal reducers though. There is no need in general to match the focal ratio of the scope to the ALPY.  You can use any focal ratio scope with the ALPY down to f4. It will not change the spectrum shape or resolution. The only reason for using a focal reducer is to better match the size of your star image to the size of the slit so you can collect more of the light and go fainter. This depends only on the telescope focal length (not focal ratio) and your seeing. If the star is smaller or comparable to the slit, then you are better off without one. Even if the star is bigger than the slit, if the star is a bright one, you may still decide not to use a reducer to avoid the risk of chromatic aberrations. 

Cheers

Robin

[Robin Leadbeater]

Hi Tony,

With your setup of 235mm aperture and f6.3, the star image size FWHM with 3 arcsec seeing will be 26 um so slightly larger than the slit width so there will be a small amount of the star overlapping the slit and it will not completely disappear unless your seeing is very good. You should see a significant drop in brightness though as the star crosses the slit.  The trick is not to over expose the guide star image. Take a look at the short videos on this page of Christian Buil’s. It gives an idea of what you should see when correctly (fente3.wmv) and over exposed (fente4.wmv). (In French but Google translates well.) 

http://www.astrosurf.com/aras/slit/method.htm

 If you still do not see the star drop into the slit, your guide camera may not be precisely focused on the slit. This should be checked first before trying to focus the telescope.

Cheers

Robin

[Denis Buczynski]

Hello all,

I was interested to see the picture of Stirling Observatory taken by Mike Frost in the members page. I visited this facilty last year when I spoke to the Stirling Astronomical Society and was very interested in the origins of the Observatory and Telescope. I put together a PDF about it for The Antique Telescope Society in New York. I have now placed this PDF for anyone to download at the following Dropbox link;

Denis Buczynski

https://dl.dropboxusercontent.com/u/43318883/THE%20OBSERVATORY%20AND%20TELESCOPE%20IN%20STIRLING.pdf

[Roger Pickard]

I’ve used Gary’s 14″ Meade for another 7 years and only this year was brave enough to try Ron’s method of Sellotape.  It still left a few marks and checking Ron’s article again he used a standard window cleaner but make sure that it doesn’t contain any vinegar.  Mine didn’t and the plate came up sparkling.  Not sure it really made any difference to the images but at least I’m happier knowing that it must be the sky conditions and not my telescope if things are not as good as I feel they should be.

Cheers,

Roger

[Dominic Ford]

Opticians sell cheap cloths called “microfibre wipes” that are designed to get grease and dirt off pairs of glasses.

I’ve always been really impressed how well they clean my glasses, and have taken to using them on camera lenses too. I’ve never tried them on telescope optics, but I guess they ought to work? I’d be interested to know if anyone else has tried…

[Robin Leadbeater]

Hi Gary,

ATel 9418 makes the suggestion that the H alpha emission at least  may be present at times weakly even in the normal quiescent state and stays at the same absolute strength but becomes more obvious as the continuum drops (ie constant flux but increasing Equivalent Width relative to the continuum)  My spectrum is not really good enough to confirm this though.

I did also have a try with the ALPY at normal resolution (Thanks to the support from the Harold Rildley grant I now have the capability to switch resolution more easily) but the SNR at this magnitude is too poor to show any more than the general continuum shape. I wonder if the Asiago team are still keeping an eye on it with the 1.2m telescope?

Robin

[Andy Wilson]

Hi Alun,

Nice spectra! I’m interested to hear about your setup as that is something I had contemplated. A low res spectrograph on a small telescope, piggy backed on a larger telescope with a high res spectrograph. I thought getting the slits aligned would be just about impossible, so I’m very interested and impressed to see that you have achieved it.

Well done!

Andy

[David Strange]

Tom Field is an enthusiastic speaker and gave a free webinar on Spectroscopy with a Star Analyser to the Norman Lockyer Observatory some years ago. He used Webex, and although he was in Portland, Oregon at the time, the transmission was flawless and it was as if he was in the room giving his presentation. I am sure he is still offering this service if you can’t make this Sky&Tel webinar.

David

[Andy Wilson]

Thanks for posting this Calum. Very interesting that spectroscopy is gradually getting more coverage.

I’m tempted to watch, but as there is a cost and it is more targetted at those starting out in spectroscopy I’ll probably give it a miss. Still very pleasing that S&T are showing an interest in spectroscopy.

Cheers,

Andy

[Callum Potter]

*** No warranty expressed or implied ***

Sky & Telesope are running a beginners spectroscopy webinar ‘live’ on Thursday, which might interest members thinking about getting into the subject.

Even if you can’t attend, you can replay the session and access the materials.

There is a cost, but it does not seem excessive…

Full details on the S&T website.

Would be interested to hear from anyone that signs up for it, and attends.

Thanks, Callum

[Richard Miles]

Yes – when the daytime sky is really clear and blue you could even try to observe the brighter stars in a GoTo telescope but beware of getting too close to the Sun, Paul. Clear skies. Richard

[Paul Anthony Brierley]

Just for fun. I have my little Willaim Optics zenithstar 66sd, mounted to my Losmandy G11.

It’s a very nice sunny day here in East Cheshire. I slewed the G11 to the Sun (filter on telescope) did an alignment. And now I am looking at Venus, Mercury, Jupiter and the Moon. All through a 13mm Baader Hyperinan eyepiece at x20

Venus looks, round, whilst Mercury is a tiny cresent. Jupiter is a large, ghostly orb. And the Moon is at crescent phase. 

Time of observations. 14:50hrs UT.