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About ollypenrice

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  • Birthday 12/02/53

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

    Do you actually need to be able to activate both of the FWs? This might sound like a nutty question but a likely shoot would be Ha all night in one and, say, RGB in the other. Or L in one and RGB in the other. You could set one FW to Ha or L, unplug it and then have the other one active. Or it might be OIII all night in one and Ha all night in the other. Very often we change filters only on one scope during the night. Olly
  2. I've had one as well. I wouldn't consider it for DS imaging. Even on a wedge it will be nigh on impossible to make it track well enough to support the resultion you'll be getting at this focal length. Instead I'd go for a small refractor or imaging Newt on an HEQ5 or better. The SCT is a nice compact visual scope, a fine planetary imager but a tall order for DS imaging. If you keep an eye on the DS imaging board here you'll see what people are using for this task. Olly
  3. Is autofocus as good as it sounds?

    If you are imaging only (and therefore need just a small range of movement at the drawtube) it is easy to make a tangent arm microfocuser like this. This is actually my favourite manual focuser for imaging and I have a standard Tak and a Feathertouch in use as well. I like it because the smallest turn you ever need to make is about half a turn. (It is 'micro' as in micro!) It also holds the focuser in position as well so there is no need for a lockscrew and no possibility of slippage. I have it in mind to make an improved version which does away with the spring by pulling on the arm as well as pushing but this one works so well that I never get round to it. Highly recommended and it cost about 10 pence! Olly
  4. Although I haven't checked the used proces lately, I remember feeling that the TV85 was one of the most under-priced instruments around. I'd love one but have not the slightest possible excuse! Olly
  5. Is autofocus as good as it sounds?

    In my opinion it would not be a good investment to buy an autofocuser for an ST80. You would do far better to improve the scope. Also the ST80 focuser is quite primitive and probably not accurate enough to work under stepper motor control all that reliably. It is perfectly possible to focus manually. The main advantage of autofocus is being able to leave the scope unattended while you get some sleep. There is a danger of coming to believe that an autofocser is necessary when clearly it isn't. Regular checks using FWHM measurement will keep most scopes nicely in focus. There are some fast astrographs which are notorious for focus drift during temperature change and these will certainly be best under autofocus but I think the idea that we all 'need' it is very strange. Olly
  6. VDB 15, QHY 367C

    That's very good. I know this area and the reflection nebulosity is really top class. Ha would lift the rest but, even so, that's a great result. I'm really impressed by this. Olly
  7. Rosette to Cone 6 panel mosaic (First Draft)

    Great and a fascinating bit of sky. (Big bit, that is!!!) Olly
  8. Is autofocus as good as it sounds?

    Yup. If ever I felt like adding three electronic devices and three extra USB connections to our setups (don't hold your breath!) I would only do so with a very non slip focuser. I do have a Moonlite which I think is about as non slip as a ski slope. Olly
  9. This is beyond weird.

    All is working as it should tonight. The wild and woolly wind is gone and photons are landing serenely in their appointed locations! Olly
  10. This is beyond weird.

    At about 45 degrees to both. Olly
  11. Great. So it was tilt. And a free solution! (Not many of those in this game...) Olly
  12. This is beyond weird.

    Yes, this has to go on the list of possibilities. To be honest the wind had so messed up the seeing that it was hardly worth collecting data at this resolution but I was keen to try. And, in fact, I lost only one sub. Since the Ha I was doing is only there for the main nebula it doesn't matter where on the chip it is as long as its there! What remains mysterious is how it moved and then delivered a perfect sub in a new place. 20 minute subs need guiding, especially at this resolution. Olly
  13. Astrodon loveliness

    Great. The NB filters, in particular, are in a class of their own. The Ha 3nm is one of the best bits of kit I've ever used in astronomy. Olly
  14. This is beyond weird.

    Would it know it was a new star? I think that, just maybe, the gusts might have been enough to cause slippage in the drive. PHD would then pick up on the nearest star, perhaps 'thinking' it was the original. To complicate matters all stars, and the target, were very faint indeed. They might not record during a short period of searching. The sensor is small and the FL quite long so the slew to the second imaging position is only the equivalent of a couple of seconds input at slow guide speed. I take on board the objections to my 'explanations' though. Whatever I can think of meets with an objection, that's the problem! Tom will be joining us this evening so we'll have more (and better!) grey matter on the job... Olly
  15. Mount

    Typo. I did mean PE. PA is, at least, reliably adjustable! Olly