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About robertm

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  1. Thanks all. I have the ASI2600MC so know how good the sensor is. I find the sensor in the ASI needs the tilt plate for correct alignment. QHY quote that their sensor is well adjusted - can anyone quantify that for fast optics i.e. the tilt plate is unnecessary ? Edit: By fast I mean f/2 or f/3
  2. Am also interested in the 268m and was wondering how good the cooling is - can it do a -40C delta from ambient ? Thanks Robert
  3. It good that yours is working well, I’m finding mine a bit challenging at the moment... one for another thread.
  4. What a superb image, great capture ! Am trying to dial in my RASA 8 and 2600 combo now so can appreciate what you’ve been through to get this right. Thanks for sharing Robert
  5. Thanks Gus. I’ll see if I can find someone who has one spare. Robert
  6. Would be grateful if anyone could help. The issue I have is that the handset firmware update only ever gets to no more than 1.00% complete before it fails; usually it's between 0.04 and 0.40%. Another issue is that I have is that it takes two attempts to retrieve the Hand Controller version as the first fails to connect. Not sure what I'm doing wrong here, could be a school boy error who knows. I've powered up the handset so it goes into firmware update mode (V1.7 firmware updater on the handset). The firmware is the latest downloaded SW (03.39.03) as is the PC firmware loader
  7. I'm also building my first using the same wireless All Sky Camera Indestructables instructions by Thomas. I quite like the way it runs continuously but only takes images during the night based on the longitude and latitude. Robert
  8. I've been following the Cloudy Nights thread on this and it seems like the original work was done by a guy called Rick Kellogg a few years ago. He wrote a paper with examples and code in which he expressed a hope that it would be taken up by makers of guide programs; this could be just co-incidence of course but PoleMaster does seem to follow the original work quite closely. Here's a link to the original paper: http://www.syracuse-astro.org/pdf/2012_August_R_Kellogg_Electronic_Polar_Alignment_Scope.pdf Quite an interesting read I found. Robert I'm singing in the rainJust singing in the rainWh
  9. I think this is where experience comes in. A lot of lenses look superb for terrestrial but as soon as you look at the bright pinpricks that are stars then that's where you see astigmatism, coma and chromatic aberration rear themselves. The last thing you want is a compromised image before processing even starts (that's my personal opinion).
  10. The main reason for stopping down is to avoid use of the glass around the edge where lens design is most compromised. I'm afraid the trade off is to make the lens a bit slower but that depends what the use is. The 200L II is definitely good for f/3.2 narrowband but for broadband (I.e. luminance) then I suspect the f/4 that has already been mentioned is where the sweet spot is. One thing to note is that at f/4 you are only using 200/4 = 50mm of aperture and that's within a knat's of a 48mm threaded filter. Also if you use a threaded filter then, as well as the f/4 stop, you won't be troubl
  11. An interesting topic, this is exactly what I went through a few years ago. My images were taken with Baader 7nm filters and I feel they worked well at f/2.8. I think the shift in band pass was still well within the filter profile. You may also want to consider filter size and how large the sensor is as well as filter to sensor spacing. As others have mentioned getting a filter wheel into the equation may be a challenge but I gave up with adding an oag. The light path is so narrow that any prism will affect the image even if you could fit it in. An alternative is to go with larger format len
  12. If you want to even consider using it wide open then it has to be well collimated (check for centred vignetting). If it's out, then because it's a professional lens, you can send it back to Canon (UK branch is Enfield I think) free in the first year for adjustment. It's very good at f/2.8 with an 8300 sensor equipped camera but I found that f/3.2 produced outstanding images (in narrow band) if you can get it focussed accurately enough; the edge stars will be squiffy if you don't ! https://www.flickr.com/photos/29673723@N04/5007278823/in/album-72157624216353110/ The next is full size unbinned
  13. It's not quite as simple as that. Unfortunately Nikon also seem to do some clipping of the black point which makes full calibration a bit of a challenge. There is a thread on my local society web site where someone has been doing some in depth analysis if you're interested http://forum.orpingt...hp?topic=8917.0
  14. Just to add. Make sure the guider sub has focus when you change the screen stretch to medium.
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