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.

sgl_imaging_challenge_banner_lunar_landings.thumb.jpg.b50378d0845690d8a03305a49923eb40.jpg

maxchess

Members
  • Content Count

    48
  • Joined

  • Last visited

Community Reputation

42 Excellent

About maxchess

  • Rank
    Nebula

Profile Information

  • Location
    Guildford, UK
  1. NGC6960 Witches Broom, taken with my shiny new ASI294MC with Optolong L-eNhance Dual-Bandpass Narrowband Filter on an ES102 scope on HEQ5_Pro: 60 x 60 secs + 20 Darks, 20 Flats, processed in Startools. Shot in a fortuitous gap in the clouds.
  2. This portrait of M27 the Dumbbell Nebula really stunned me when it first emerged from DSS, it only needed a light touch in Startools. Taken with an ASI174MC uncooled on a ES102 triplet, under Bortle 5 Skies: 80 x 60 secs + 20 Darks + 20 Flats. A real gem of the night sky. Hope you like it. Max
  3. I have decided to buy an OSC CCD and have narrowed it down to a choice between AS129MC Pro and the ASI183MC pro. I would welcome some advice and comments on my reasoning. First, I know there is a good argument for going mono, but that’s for the future. I want to take it one step at a time. I am just about getting my head round guiding. My kit is a HEQ5-Pro Rowan Belt modified with mainly Explore Scientific ED APO 102mm f/7 focal length 712mm permanently mounted on a pier.. I also have a Celestron C8 but that’s for later. Until now I have been imaging with a Canon450D moded and a Canon 2000D. I have an ASI178MC (not cooled) that I bought to experiment with last year. I also have travel gear consisting of an AZ Gti WiFi on which I sit my DSLR with a Cannon 300mm lens, which is great for big targets like M31, Rosette Nebula etc After extensive reading on Forums etc I am leaning towards the ASI294MC-Pro. (but tomorrow I might change my mind) My reasoning is that the ASI1294 has a larger sensor size, 14 bit ADC vs 12 on the183; and larger pixels, and a greater full well capacity. So this means that the FOV will be only just a bit tighter than the my DLSR so with my ES102 I can still get good images of larger targets like M42 especially if I add an FR. Without the FR I can get smaller targets. I should also be able to use it with my Canon 300mm lens when traveling. It should also work well with my C8 when I start using that. I have also read that the larger pixels at 4.63um are more forgiving than the ASI183 that has 2.4um pixels especially when focussing. The ASI294 also has a much greater full well capacity, in theory providing greater dynamic range and less chance of blowing out stars. But I have a nagging doubt, because the ASI183MC pro although it has a smaller sensor size, is still quite decent and the tiny pixels mean that it has a resolution of 20mp compared with the 11mp of the ASI1294. So am I turning my back on greater resolution for my shorter focal length scopes? In the world of DLSR 20mp beats 11mp any day. Plus the ASI183 has an 84% QE! What brought it home was a test exposure I did with the old ASI178MC that also has 2.4um pixels, but a much smaller sensor. Using the ES102 I took 50 x 30 sec exposures of M27 (dumbbell) and compared them with results from the 450D on the C8. The FOV is the same, but the 178MC results were so much better. Any views most welcome.
  4. I have the AZGTI mount which I use in EQ mode. On it I have a 300mm canon lens with either a DSLR or an ZWO camera. The most balanced way is to use a Tripod Collar, round the lens £11 on Amazon and attach that to a short Vixen type dovetail bar around £20 , although you can pay up to £100. Make sure you get one with a captive screw designed for mounting camera, like this one:. This arrangement allows you to balance the camera in the Vixen mount by sliding the bar. The ZWO adapter you quote should work too.
  5. Martin, Can you descibe how you fitted your garage door opener? I am planning to upgrade my obs rails to female vee section steel wheels running on male vee section steel rails and then to add a garage door opener. The Easygate system you linked to looks good value for money.
  6. Do you already own an DSLR? If so have you used it with the Nextstar? If not I suggest you look for a used Canon 450D, ideally astro modified.
  7. My Christmas present was a Canon 300mm f4 lens to use as my travel scope instead of a bulky refractor, but to go with DLSR and AZ/GTI portable mount. So I took it to La Palma to get some winter sun and dark skies. Playing with Stellarium told me that with a 78degree tilt I should be able to get both M42 and the HH Neb in one frame, no mosaic. It's true you can! So despite losing half my subs to a faulty cable I got 60 x 30 sec exposures, which at f4 in really dark skies got me a reasonabe result. Taken on March 12th in sunny la palma : Canon 2000d unmodified, 300mm f4 lens, on AZ-gti mount. Controlled by ATP software (great canon autofocus control, wifi connect to mount, plate solving for positioning) processed with DSS, Startools and Lightroom. 60 x 30 sec subs +20 each of darks, lights, bias
  8. Thanks all, for some really helpful advice. I have only been imaging a year and just started exploring guiding. Before that I was doing up to 120 secs unguided and getting (for me) decent results. My best image was https://astrob.in/373575/0/ 160 x 60" unguided and I am interested in your comments on what is achievable with my HEQ5 Pro if I guide it. At present I am trying just to get sub 2 arcsec guiding but seem to be getting bad backlash related errors errors. Once achieved it sounds like I need to stick to my DLSR through the ES102.
  9. I am experimenting with guiding, and want to understand what I need to guide my ES102 with a ASI 1784 on an HEQ5-Pro. I have an Orion SSAG mono guide camera and its 50mm guide scope, fl= 162mm. I also have an ST80 fl=400mm. I am having a bit of trouble guiding with the ST80 using PHD2. I get large guiding errors. I am considering going back to the Orion 50mm. However when I calculate the FOV for the ES102 + ASi1784MC I see it is 0.6° x 0.4°, which is equivalent to DLSR on a 2100mm focal length scope! Therefore I wonder if the 50mm/162mm FL will cope. In the discussions on Focal Length for guiding I only find references to matching the FL of the main and guide scope, not the FOV, but surely its the FOV that affects the apparent angular motion and therefore the required guiding accuracy? Or have I missed something.?
  10. OK, sounds good. Moon washed out last nights images so waiting for Moon to disappear before experimenting further.
  11. This is the article that gives the example settings for long exposures. It is a different sensor, but the principal seems to be that for Highest Dynamic Range on long exposures you set gain to 0, offset 10. In the example they have unitary gain as (G: 139 O: 21). So I assume that G=0 maximizes well depth and offset 10 lifts the lower values. In my simplistic way of thinking I assume that with G=0, O=10 I can usefully increase exposures until the highlights reach saturation, at which point I am getting the best dynamic range, ie making optimum use of the ADC to record the widest range of values in the most detail. I notice from Astrobin that many ZWO camera users use large numbers of relatively short exposures 60-120 secs , rather than DLSR users who go for fewer much longer exposures. Still struggling with this camera, will process last nights Moon affected images later.
  12. To be safe I am trying some captures at Gain=10 , Offset=10 on M81, (20 x 120 secs) but with a full moon they are likely to be poor. M81 is about as far away as I can get from the Moon. However lights so far are showing minimal Amp Glow. Hopefully with Darks, Lights & Bias I can eliminate it.
  13. I have the uncooled version of this camera and the same problem. I tried Gain=200 and got what looked like a star shaped light leak in one corner just like yours. I also took flats & Bias frames, but they did not help much. I assumed it was a problem with my scope, but found its was AMPGLOW, see this ZWO article. I tried taking 90 second Darks at various levels of Gain and found it diminished until it was virtually invisible at Gain=10 . To see the effect take a Dark into your processing program and stretch it. ZWOs solution is to control via Darks and disable any dark optimization feature of your calibration program eg DSS. They say that this effect only occurs in "specialist" sensors and not in those used for DLSRs. I was staggered, sounds like a design fault to me. These guidelines appeared in another ZWO post: Unity Gain ==> Gain: 180 Offset: 25 Highest Dynamic Range ==> Gain: 0 Offset: 25 Lowest Read Noise ==> Gain: 270 Offset: 340 So my interpretation is to go for Gain: 0 Offset: 25 for DSOs on long exposure and disable dark optimization. Waiting for moonless/cloudless night to try this out. Any other experiences most welcome. Never had this problem with my trusty 450D.
  14. Ok, as i write i am finally guiding using the 90mm fl500mm frac on my C8 with the Orion SSAG camera. I am using the internal guider with Indi Ekos on a Rasperry Pi3+. This allows me to sit inside and track progress via VNC on a tablet or laptop, All seems fine and the camera can find stars with the gain turned up to 70 out of 100 on the SSAG. Seems to be keeping within the 2 arcseconds limit most of the time, but my Polar Alignment probably needs some work. I also think I am guiding at the limit of my EQ5-pro weight. Currently the total weight of the two scopes and the cameras etc is 10.2 kg. I think the max for imaging is 11 kg. I am only doing 200 sec exposures because its M2 and quite bright, but the surrounding stars look sharp.
  15. I followed that advice and now get the prisim fully iluminated, by day I can see distant trees clearly full frame in the oag guide camera and the main camera image seems unaffected. The problem is that at night the very few available stars are too dim to guide on. The Orion SSAG and the ZWO ASI 178MC do not seem sensative enough despite adjusting gain, applying darks and various transformations. I can guide ok with a 50mm guidescope but not with the oag. Everything I have read elsewhere confirms this view and while it might occasionally possible to use a cheaper camera , to get reliable OAG guiding at long focal length you need a very sensitive guide camera, like the lodestarx2. So I am going to plan B and mounting a 90mm fl500mm frac on my C8 and try to guide with that. Should be a lot more photons.
×
×
  • Create New...

Important Information

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