Jump to content

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.

FaDG

Members
  • Content Count

    271
  • Joined

  • Last visited

Community Reputation

140 Excellent

2 Followers

About FaDG

  • Rank
    Star Forming

Profile Information

  • Location
    Rome, Italy
  1. The main driver for the scope is to check whether your DSLR reaches focus. Not 100% sure, but I might have read that 130pds allows a DLSR to be focused, the 130p doesn't. There's a whole thread here on imaging with the SW 130, you might ask there. For the mount, either an EQ3, but a bit at its limit, or AN EQ5, way better (and more expensive, obviously)
  2. Yes, the Bresser Goto 80/400, bought and tested it for a newbie friend. Unfortunately, out of the box, the dec drive did not manage to raise the scope (there are a couple of video on youtube showing the same issue) and the scope was horrendously out of collimation. Contacted Bresser that showed an excellent customer service: the scope was sent back at their charge and we received it after about one week. Gears working perfectly now and lens improved. Now, this being said, it's not the best 80 f5 sample I have used, the tripod is quite shaky (tradeoff between stability and portability) and the controller SW is not up to Synscan Level. BUT my friend is now very happy with it, it gets a lot of use and the Goto is very helpful for a beginner, which is ok for the price. So, if you look for optical performance, choose something different (and more expensive if interested in goto). But if you wish for something extremely lightweight and portable, to start exploring the night sky with the help of goto (precise enough to place the target in a low mag eyepiece), then it could be a good choice. It's just a matter of expectations. I agree that the AzGti is probably a better product, but the Bresser was quite a bit cheaper. Then, what are you interested in? If lunar and planetary, a Mak is better value, for deep space a short and fast frac has the edge. Plenty of targets can be enjoyed with 80mm, although a Dob will show you a lot more. But I wouldn't leave that in the car! Ah, by the way: years ago I used a Meade ETX70 (70/350 refractor), the mount was ok, on par with the Bresser, but the optics were seriously astigmatic
  3. Knock Knock. Joined late and waiting ti be accepted. Somebody could let me in, please? Thanks! Just done
  4. It depends on what you mean by "overexposed". Once you saturare the well depth, information is definitely lost for those pixels and no kind of post processing can get it back. So, take care to avoid saturation by reducing ISO (or exposure time) in order to better exploit the dynamic range. The other way to get around that is to compensate with shorter exposure and blend them into the saturated areas, but I don't find it a simple task, still to improve
  5. Normally Synscan ends slews always from the same direction in order to recover backlash. So, the movement you 're seeing may be not peculiar , just coded. You may try this: Go further away with your movements and then manually return slightly towards the home position. In this case the mount shouldn' t go further away on its own
  6. Having purchased most of my setup used I, as buyer, would have proposed to use the scope for a reasonable time (according to weather) and have the right to return it in case the performance wasn't satisfactory. But in the end, it seems everything turned out well, so I wish the new owner to enjoy it. Personally I'd have bought it immediately, but living in italy it wasn't just that easy.
  7. You could give it another go... Do you have a laptop? Just download a free Platesolver or connect to Astrometry.net and submit your image. You'll get a precise information on the centre and field of view. Using that knowledge and your planetarium software it will be much easier to find the target.
  8. Frankly not easy to see in those images, but if the elongation is even across the field, and trailing is to be excluded, then you may have a slight astigmatism issue. If this was the case, then reason for changing during the course of the night might be change in temperature causing the OTA to slightly contract or optics to adapt and hence focus shift. Moving away from focus could justify elongation increase.
  9. I've had a lot of grief with my flats too! I tried different exposures, different methods to acquire them. Then, recently, I found the solution. How did you shoot those flats? If not already done this way (in which case I don't know how to help), try taking then again tomorrow, in full daylight with a white T-shirt on your lens and pointing opposite side of the sky wrt. the sun. Head for 1/4 ADUs of your full well. It was really the one and only way I solved my flat problem.
  10. Hey Greg, the address he states is within 10km from my place! Tell him that you're interested and a friend of yours will pass by, pay cash and collect the item directly. Let's see how he reacts.
  11. Well, finding M81 in Leo will certainly prove difficult! ( tongue in cheek) Seriously though, there are different solutions: several members suggest fitting a red dot finder to the dslr hotshoe as you're now prepared to do, and using it to point it towards your target. Obviously a basic knowledge of the sky and a sky chart is needed. Personally, I don't use an added red dot but the LEDs inside the viewfinder. It works perfectly. Another solution is to point the camera in the generic DSO direction, take a shot and Platesolve it, applying corrections as needed knowing the target coordinates.
  12. Then I assume that the stacked dark you used was acquired in a much warmer condition, which fully explains the issue: a dark is only usable for a small temperature range, and ideally darks should be acquired each session. The thermal noise in your dark Stack is much higher than during the lights, so you're removing more signal than needed, henche the holes. Reshooting the darks (at night!!) will solve the problem
  13. May I still suggest another test? Properly align your camera such that RA axis be either purely horizontal or vertical. Test this with manual motion and very short shots. Now, strongly misalign your polar axis wrt. to Polaris, let's say 10 or 15 degs higher or lower. This will induce a dec drift (and a small RA speed variation, take it into account). Point your scope eastwards or westwards, set ISO to minimum, centre a decent star, stop down your scope if you have any means for that or use filters, and launch a single 10-20 minutes exposure. You should get a loong trail in the dec direction: ideally it should be purely a line, but if your scope tracked ideally you wouldn't have started this thread! So, you'll rather see the PE curve superimposed to the line, and a possible drift shown by an oblique drift. Based in the system resolution (arcsec/pixel) it is possible to infer the error. Specifically, the curve should repeat every 10 minutes. Post the result here and we'll try to troubleshoot. I'll be surprised of any backlash during pure tracking.
  14. They ended up dark because you only used one Dark frame in the calibration process, which is exactly the reason why you should average darks: if you don't, when the dark is subtracted from the lights during calibration, values could drop below 0 and leave you with those black holes; also, with only one dark you're actually adding noise into your Stack, mainly in the background. And, while you're there, also add bias and flats too (and dither, as was suggested): this will give you the best data to start with, and due to the low signal reaching us from those far far away galaxies, you'll really need that!
  15. Hang on... Does this only happen with EQMOD? Have you tried the Synscan handset? Unless it is caused by uncommonly high PE, I'd rather think of a SW issue more than a mechanical one. Just out of my mind: maybe you have a (now) invalid PEC table saved in EQMOD, which causes unwanted corrections to ruin your tracking?
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.