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CCD Imager

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About CCD Imager

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    Star Forming

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    Cambridge
  1. I bought mine in May and used it about 3 times, its a superb lightweight mount which is so easy to pick up, set up outside and get going. Its quiet and handles small scopes easily. Periodic error, which I measured was around 15 arc secs and nice and smooth. I also bought and fitted the Ipolar which works like a charm. The CEM40 was released shortly after and I ended up buying that to support my FSQ which would have been at the CEM25p's limit. I am planning on selling the CEM25p, although havent advertised as yet. Adrian
  2. As you are using a DSLR, then taking photographs of bright stars looking for blue bloat would be helpful.
  3. I'm always wary of Trevors reviews, great chap that he is, he never says anything bad about any astro kit..... I would be interested in whether focus changes between filters, FWHM of blue images compared with red and green and of course, stars at the periphery of the FOV. Adrian
  4. Yeah, three years late, lol I actually bought the WO Redcat earlier this year, but I would still be interested in seeing how the Tecnosky performs.
  5. As the rear elements are fixed at the factory, they are very unlikely to move. The front two elements are adjustable and would be the likely source of any miscollimation, as it was in my case. I had an FSQ with exactly the issue you describe and that needed to go back to Japan and I had a replacement. I don't have much luck with small refractors!
  6. Steve's right, you need to be knowledgeable about optics before attempting collimation of a refractor, especially ruling out other potential causes of mis shapen stars in an image.
  7. Hi Steve I would agree, if you are inexperienced with refractor collimation, then don't start. I've done a few in my time, previously using the Tak collimating scope to good effect, but I dont have that any more. A petzval design is two doublets, one at the front of the scope and one at the rear. In the Redcat, the one at the rear is fixed and cannot be altered. The front two elements have 2 sets of screws at the 12, 3, 6 and 9 position. It's honestly as easy as collimation a Newtonian, if the coma becomes worse, just reverse the change you made. Can you do harm? Over tightening can cause pinched optics and worse, damage the cell, I tighten the collimation screws until I feel resistance, no more. My only issue is that I dont know how the collimation screws work as mentioned above, but Im finding out by trial and error Steve, I didn't buy from FLO and this is my second Redcat. I returned the first because of mis collimation, but as it was also present in the second and I really wanted to keep the scope, I just had to collimate myself. Once collimated, it is a very nice little widefield imaging platform. I did also note that the collimation screws were a little loose when I first got the scope, I checked this after I found collimation changed when pointing the scope 120 degrees to a different part of the sky. Adrian
  8. Been a busy last few months, but I have recently been able to assess my Redcat more. I did post a mini review a few months ago and there were some comatic stars in a corner due to mis-collimation (as it transpires). If you unthread the dew shield exposing the lens, you can see 4 sets of 2 collimation screws, each pair seperated by 90 degrees. I really dont know what they are doing, is there a set screw and adjustment screw per pair or perhaps they sit either side of the lens cell. Any way, by experimenting, I managed to improve the collimation by going back and forth between opposite pairs in the direction of the coma. If any one actually know what the pairs of screws do, I would love to know. My second observation is that the Redcat is not a typical Petzval design. Usually there are 2 doublets at a fixed distance apart in the OTA and focus is achieved by moving the telescope focus to achieve the correct distance from sensor to rear doublet optics. However, the redcat is focused by moving the front two elements and hence the distance from the rear 2 elements from the sensor is crucial and fixed. Therefore, please insert the correct adapters to achieve the required distance of 77.7mm. This may explain the comatic stars in some peoples images? My collimation is nearly there and I am much happier than before. Of course you can return the scope to the supplier, or if you are confident, adjust the collimation yourself. Adrian
  9. Most astro software programs have combine sigma reject algorithms that will do a good job. The secret is to have many sub exposures for the software to be effective. Generally, more than 10 subs will easily deal with aircraft trails. You shouldnt need to buy new software!
  10. Because its a quadruplet design, you dont need worry about spacing. The spacing is the focal point behind the rear 2 elements and there is plenty of focus travel to achieve this with a DSLR or CCD/CMOS camera. Altair Astro or Ian King Imaging both sell M48 to T2 adapters that will connect the ZWO camera to the scope.
  11. I agree with you and I will be able to determine this the next clear night and hopefully the cause
  12. Yes, the Star Adventure is the exact mount I will take on holidays with me Adrian
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