PhotoGav

Mmm, interesting. Why have you chosen the SA200 rather than SA100? What kit are you using? I am trying to establish which grating I should purchase. I have two telescope options: a Thomas Cooke 10” refractor or a SkyWatcher 200pds. I will use either a DSLR or a ZWO ASI 120-MC. My investigation suggests that the SA100 with the 200pds & asi 120 is probably the sensible option. However that needs to be set up outside each time for use. Meanwhile the 10” refractor is permanently mounted in an observatory - I would much rather use that. The SA200 would be the better choice for that, I think.

I wouldn’t gamble on that! Thanks Vlaiv. Fingers crossed. Distance calculation with spectroscopy, photometry and the distance-modulus equation is exactly what I am trying to do.

Thanks John, I’m going to take that as a ‘yes’! I look forward to comparing notes as we progress in this branch of astronomy.

Congratulations on taking your first steps into guiding. Your images will benefit hugely! Filters - no, you won’t need to fit any filters. The more starlight the better to find a guide star. Clouds - if a cloud covers your guide star, PHD2 (you mention PHD above, I would recommend going straight to PHD2) will report that it has lost the guide star and beep at you a lot! If the cloud passes quickly and your polar alignment is good, when the cloud has gone the guide star should be in a very similar place and PHD2 should pick it up again and carry on guiding. If the star has moved outside the green box in PHD2 and can’t be found, you would have to select a star and start guiding again. It will all become very apparent as soon as you connect everything up and are pointing at stars. Good luck with it all.

I am investigating the whole area of spectroscopy on a budget... how ‘easy’ is it to establish a star’s spectral type by using a Star Analyser? Would I get any usable results or is this a step too far for the humble amateur astronomer?

That would be now then! Pouring out there... I will investigate and experiment. Thanks.

@tomato - I ended up completely redoing the mastic around the outside of the base of the dome walls fairly soon after the install. It was leaking quite badly. I gunned it up good and proper and it is acceptably waterproof now. @Laurin Dave - was the water obviously coming in from the door frame? I think mine is coming from the join in the two dome quarters that ends up over the door. I wouldn’t want to move the dome round to put the shutter over the door and end up with the drip coming in through the join now rotated around 90° because that would be in my electrics / computer zone!

Ooo, this is intriguing... please explain yourself a little more! The only problem I have with my Dome at the moment is slight water ingress just inside the door when it pours down. Try as I might, I can’t work out where it is coming in... so very interested to hear your experiences.

I have a green Pulsar Dome and it is my favourite toy in the whole world throughout my life! It certainly gets hot in there in the summer, I’ve seen 40+°C on the temp gauge, but everything survives with no problem. The benefits of having a ‘camouflaged’ dome that is acceptable to the current Mrs PhotoGav outweigh any small peaks in man dome internal temperature! I often open the roof & door when it’s really hot - sometimes to point the solar scope at the thing generating all this heat...!

I'm having flashbacks to panic checking the water levels round the back of the campsite... arrrgh! Let's hope for a calmer and more star focussed party this year. Having said that, I have very fond memories of looking through a huge, beautifully made Dob last year and being stunned by the views. Can't wait for the event, whatever the weather. See you all very soon!

I have just seen on the SGPro forum that QSI are about to release ‘their next generation of drivers’. Is anyone aware of this? Any ideas what will be different? I just can’t stop thinking ‘if it ain’t broke...’!! Argh...

Love this, what a great project, congratulations. Above all I love the image that all of this has made possible. Excellent field of view and composition. Look forward to seeing the completed image. Good luck with it all.

I prefer the second image. It is not as ‘spikey’ as the first, which, to me, appears over sharpened and over noise reductioned (if that’s a word!?!). The second has good detail and is more naturally soft looking. The stars are tighter in the second one too. I’m intrigued to know which image was with which camera... As for likes - if that’s what you are after, post on Instagram or Facebook!! This forum is all about sharing knowledge and helping each other to get the most out of this most excellent pursuit (note I didn’t say hobby, I think most of us are way beyond hobbyist with our dedication!). Keep it up Rodd, always enjoy your images and posts. Finally, on a personal preference note, I would love to see redder H alpha areas rather than the false orangey colour. As I say, that’s just what I like!

Excellent, sounds like you are already equipped to do this! I am an SGPro user these days, so can’t give you exact instructions on how to use APT to do it, but I’m pretty sure it is possible. Have a read through this and you should be able to suss it out: https://ideiki.com/astro/usersguide/pointcraft_and_plate_solving.htm?ms=AAA%3D&st=MA%3D%3D&sct=MA%3D%3D&mw=MjQw Good luck, it is definitely worth mastering. One thing, try and avoid moving the camera orientation on the scope between imaging sessions if you can otherwise you need to match rotation as well!

There are two methods to get back on target for multiple nights of exposures. The first is manual - attempting to match up the position of bright stars by eye until you are pretty much in the same framing. This is time consuming, inaccurate and difficult. The second method is to do that automatically with plate solving. You need to be hooked up to a computer to do this. The sequence is: slew to coordinates of your target, take a picture, software compares the stars in the image with a database of stars until it finds the exact coordinates of where the scope is really pointing. The scope is slewed to point at the target coordinates again. Take a picture, plate solve, move, repeat until the scope is pointing exactly (or near enough) at the target coordinates. This is quick and easy to do once your system is hooked up to a computer. Imaging control software such as APT or SGPro can manage this process for you. Hope that helps.

My plan is to introduce practical spectroscopy to the pupils studying Astronomy GCSE and Physics A level at the school I work in... I need to become vaguely proficient in it myself first though! I may have questions for you...!

Whilst I am an imager, I am increasingly becoming an observer too. There is much enjoyment to be had from looking at people's holiday snaps of a beautiful lake in a far flung corner of the world, but to go to that lake and see the misty sunrise for yourself is unbeatable. I suggest that the view through the eyepiece is like going to the lake. I will never tire of the reaction people have to a clear view of Jupiter, Saturn, Albireo, M13, M42 or M31 (and so on!) through the telescopes at the observatory where I now work. Even the most seasoned observer still gets a thrill at seeing the Cassini Division on a still night. No number of Hubble images, etc, can replace that awe, despite the difference in 'quality of image'. The most satisfying activity is introducing young folk to the night sky and all its delights. I think that visual astronomy takes time and effort, but it is so worth it. It is our duty to pass on the enthusiasm and curiosity in the universe around our tiny planet to the next generation(s). So, if you enjoy a bit of visual, don't keep it to yourself, get to an astronomy club, a school or anywhere and share your passion. Let's ensure that what John questions at the start of this thread is not allowed to become true. Imaging will always be of interest and let's not be frightened by that. It is a great way of sharing the interest and attracting people to the eyepiece!

Very interesting - thank you for sharing. This is an area that I am about to embark upon and so these notes are very useful. It does look ever so slightly frighteningly complex though... Like all things involving telescopes, filters and cameras, there is a steep learning curve to clamber up!

I feel your pain... It is ridiculously frustrating to have an 1800s narrowband sub aborted at 1700s just because PHD2 lost the guide star for about ten seconds. I always console myself with the fact that if it is cloudy enough for my Lodestar X2 to lose the guide star, I would have been collecting sub standard data in that sub, so it is improving the quality of my final image by aborting the exposure. [My therapist is very good!] Definitely need to have the sequence recovery option active in SGP to at least get things going again. I'm not sure of any way of altering how long the guide star can be lost for before the exposure is aborted. One for the SGP forum methinks. With regards to version updates of SGP, they are working on introducing some of the v4 functionality through v3 betas. The current beta (v3.1.0.242) is really quite stable and has fixed loads of issues. I can't even remember v2 it is that long ago, but would have no qualms in recommending v3 (my favourite feature is restarting a sequence when it is Safe after Unsafe has aborted it - love it, fire and forget while I sleep is ever more possible!). v4 is probably quite some time off, but they are very reasonable at offering good upgrade terms when you purchase a version that has a major upgrade soon after the purchase. Interested to hear of any control over PHD2 star lost parameters that you may discover.

What a cultured post! Good to see you back at the scope and hope you get plenty of time to relax with the skies. Love the RGB version. Is a mono Moon a thing of the past?!

As astronomers, we love observational evidence!

Good question, personally I would use APP in multi session mode to make stacks from all subs per filter. I would take care to ensure all calibration frames are correctly assigned to their appropriate sub sets. Whether better results are obtained from stacking all subs in one go versus stacking stacks is not something I know the answer too... interested to hear what others think.

Looks like great progress is being made! I’ve just checked and I paid £565 for an electrician to connect up my obsy (about three years ago). That included a whole new consumer unit in the house, armoured cable to the obsy (20m ish) and three double sockets in the obsy attached to a piece of board that he fixed to the dome wall. So I reckon £460 is about right. Exciting times!

Welcome in, that’s quite some entrance!! Have I seen you on the SGP forum? Enjoy the wealth of information, help and advice here. From the looks of your image, you will have plenty to offer too!

I would avoid this lens... I believe that lens fungus can spread and you wouldn’t want to pay to infect your other lenses! It looks very marked, which probably won’t show specifically on images, but will affect overall performance of the lens. I never rated this mark I version of the Canon 100-400, it just never seemed to work very well and the push pull zoom on the same ring as twist to focus drove me mad! Having said all that £100 does seem a steal...