Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Welcome to Stargazers Lounge

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customise your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.


Advanced Members
  • Content count

  • Joined

  • Last visited

Community Reputation

14,348 Excellent

About ollypenrice

  • Rank
  • Birthday 12/02/53

Contact Methods

  • MSN
  • Website URL
  • Yahoo

Profile Information

  • Gender
  • Interests
    Imaging, Cycling, Thinking, Literature, French culture, Mountains...
  • Location
    South east France, Lat 44.19N.

Recent Profile Visitors

7,415 profile views
  1. Super. A rich, deep dusty background sky and delicious star colour. As Barry says, 'refreshing.' Olly
  2. I do know the answer, having tried it briefly many years ago. Motor racing... Olly
  3. If running remotely with an automated weather system the big decision in pier height is whether or not roof-scope collision will be possible or not. You can make a system in which the scopes have to park before the roof shuts or one in which it can shut with all scopes in any position. In my opinion it is pure madness to consider a system in which collision is possible at all. One day it will happen. This has a considerable impact on pier height and/or whether the roof and upper sides or just the roof roll off. I think a rolling roof can be pretty secure when shut but, obviously, not when open. You could have heavy steel horizontal bars (like bolts) on the roof rolling into heavy steel hoops or tubes on the walls in the shut position. You need something like that for anti-lift anyway. Olly
  4. The Hyperstar is quite a tricky beast despite what Starizona would have you believe. Atik make some cylindrical bodied cameras which won't intrude into the light path but if you want to use a mono camera you have the filter problem to deal with. You can't put a filterwheel in front of the objective so you would need to seek out a slide drawer. I don't know who makes them but it's the kind of thing to look for at Telescope Service. It strikes me as a bit of a palaver but I've never tried it. Going for a one shot colour camera would solve the problem but mono is more productive. I'd have thought this would be a good match: Before believing all the optimism on the Starizona website about 'unguided' and 'alt az' I'd have a good search around on the net for real results being posted. Olly
  5. Simply bonding insulation board onto the inside using contact adhesive (or whatever) will nail condesation completely. Olly
  6. Many UK amateurs have only the roof rolling off because their horizons are not useful due to obstructions and light pollution. If this is the case for you then why not, if the containers are about the right size? (Are they not a bit big??) In our case we want to image down almost to the horizon so we have both the upper sides and the roof rolling off. I don't think containers would lend themselves to this construction. Olly
  7. Pixinsight may have sorted itself out by now but twice I've had folks here saying, 'Why don't you stack in PI? It's easy, watch. Oh. Oh, why did it do that? Hmm, let's try it a different way... etc.' So I still use AstroArt! The logic of the layout for stacking is impeccable and transparent. There's a good suite of filters which work. Column or row removal, hot pixel filtration etc. Also AA is supernaturally fast. I don't realize this till I see other programmes being used. I'm sure there are lots of good ones but I'm very much at home in AA and using its defect map (bad pixels) instead of darks has given me the sweetest stacks I've ever had. Registar is not a calibration programme, it only does registration and image combining. You can't use it for applying darks and flats etc. It is, though, incredibly useful for doing what it does. Olly
  8. I don't know how to measure it properly* but I go off my FWHM readings for that scope/camera when focusing. I know from experience what the lowest values to date are, so I just base it on that. (In the TEC at 1.8"PP 1.1 is the broadband best while in the Taks at 3.5"PP I can hope for 0.85. If I'm well away from those values I'll shoot colour and set aside the luminance for a more stable night. However on the ODK14 (0.66"PP) we found FWHM entirely meaningless with values flying all over the place so I can't help regarding your big RC if you have the same issue. Olly * Edit: homework: To read about how FWHM works you could scroll down the the section dealing just with that. I thought I understood FWHM but there are things here that are new to me. It's a very good article.
  9. Well that looks pretty darned good to me. I could live with it as is, though I'm not of the pixel peeping mindset. A few dabs with a recorded 'star rounder' action in two of the corners would sort it completely. It might just be the disance to the reducer, anyway. I'd call that nailed to within a gnat's crotchet, as Humphrey Littleton would have put it. Olly
  10. I would always run the cooler for taking flats but haven't ever found them to be particularly temperature sensitive. I think the issues will be 1) that flats can introduce noise into an image so should be taken cool to reduce this and 2) that the bias needs to be reasonably well matched when used as a dark for flats. As Martin says, don't double subtract the bias. I hope you like AstroArt. I certainly do. If I can help on getting going just drop me a PM. Olly
  11. It means that you give DSS a master bias in the place where you would normally put a master dark. Simple as that. For your own clarity of mind (if, like me, you are easily confused!) then you could make a copy of your master bias and call it BiasAsDark or something. That way the programme won't be confused by seeing the same file name in different places. It might not like that. I don't use DSS myself and stack in AstroArt, which I can heartily recommend. Although you can throw all your 'from camera' files (sets of bias, flats, darks, lights, etc) into it for it to deal with en masse, I never do that. I make masters of darks, bias, and flats first. I know I'm going to want to re-use them so it's easier and saves disk space. I will just put all my bias into the box for images (not bias) and ask it to average combine them without alignment. That's a master bias. Same thing with darks, if you use them. When I make my flats I put the flats into the images box (not the flats box) and the master bias into the box for darks and again average combine them without alignment. That's a master flat. Olly
  12. If you're using Atik's very likeable Artemis Capture then all you need to do when setting up flats is look at the white point value in the Display window. As Steve says, get this to about 25000 and that's fine. Darks and bias should not, in my view, be done on the scope but off it, using the metal screw on cap provided by Atik. When I experimented with light-excluded on-scope darks I found they were very different from darks done off scope. 30 minute darks really showed the difference but it will also be there in shorter ones. That's the price of a sensitive chip. I have no idea how the light got in, but it did. When you've shot your set of flats and made your master bias, use the master bias as a 'dark-for-flats' or 'flat dark' when stacking your flats. There is absolutely no need to bother with dedicated darks-for-flats because, at short exposure times, they are insignificantly different from bias. If you are observatory based and don't change your kit around I would say that re-shooting flats every time is a waste of effort. I find mine may last for six months if I'm lucky. It soon becomes obvious when a new dust particle has entered the light path. Also, if your scope has a well made rotator and focuser, rotating the camera will not invalididate your flats because everything that imposed itself on the flat is being rotated as well. Nothing on the objective appears on flats. (Just think of secondary mirrors...) If your focuser sags or your light cone is assymetrical then you will need to re-do flats after rotating but on our three imaging scopes the flats work perfectly after rotation. You might find that you get better results without darks. I do, as do many others. I use a master bias as a dark and a bad pixel map. This gives me consistently cleaner results on our very noisy Kodak full frame chips then I ever had using darks. A combination of dither guiding and 'master bias as dark' might well work sweetly on your nice clean Kodak chip. Have fun! Olly
  13. Another good one. Olly
  14. I don't think the behemoth will see service as a deep sky imaging instrument. I reckon it will be best employed as a visual scope and, perhaps, as a planetary imager for those so inclined. The TEC has done well on the Ghost in the past, though. Olly
  15. That's a real charmer of an image. Although small the galaxy is twinkling with exquisite details. Very fine indeed. Olly