SyedT

Here's the stacked image with the 0.7x reducer (60x60s each of RGB). Cropped by approx. 300 pixels, mainly for centering and edge artefact reasons. Stars look OK!

I'm not saying it's washed out at all, quite the opposite actually! I think you've blended Luminance very nicely here, which is why I was asking. I'm in a Bortle 5 zone so not too bad, but have streetlamps right next to me which means my exposure times are fairly limited.

Lovely rendition, really liking the colours! Did you not find that 900s exposures in L washed the image out?

Thanks! I'm hoping to do planetary work mainly, so seems like 290MM was a good choice.

That was my thinking but wasn't 100% sure. The CCD suitability calculator does say oversampling is OK for planetary/lunar imaging etc Thanks guys! Bit the bullet and went for a 290MM earlier on, on the basis of frame rate and FOV.

I'm just as clueless, but not complaining!

I've tried all of the ZWO cameras, and they all oversample. I think it's fairly unavoidable due to the FL and pixel sizes being used.

Thanks for replying John! I've already used the calculator and it seems both will give me a degree of oversampling for "OK" seeing, slightly more with the 178MM (0.13 vs 0.11 arcsec/pixel with barlow, 0.29 vs 0.24 arcsec/pixel without barlow). Not sure where that leaves me really!

Having looked around a fair bit, I haven't found much in terms of comparison between the ZWO ASI 290MM and 178MM. Their prices are identical, and the main differences seem to be pixel size (2.9 microns vs 2.4 microns), resolution (2.1 MP vs 6.4 MP), max frame rate (170 fps vs 60 fps) and ADC (12 bit vs 14 bit). I would be using it with an Edge HD 8 for planetary and lunar work during this summer. I have a 2.25x Baader barlow which I can use with the camera. Would appreciate any advice regarding which camera I should go for. Cheers

Considering the collimation is holding and will be better retained with the original screws, I might just return the Bob's Knobs to be honest. Your account will take a hit either way, it's a shame the adapters cost extra. I didn't bother getting the M56 adapter for the camera side as I already had the F56-F54 adapter lying around, which helped to bring costs down. Anyway, I've done my job by making the choice even more difficult for you, so good luck!

Better picture here without the cable interfering with the star shape. I'm getting an HFR of between 1.56 and 1.69 in SGP which is pretty good!

Cheers! I've only had one outing with the zoom so far, but it's excellent. Solidly built, the clickstop mechanism is very smooth in the Mark IV version. I wasn't keen on buying multiple eyepieces as I don't do much visual, so this fit the bill perfectly. I think I'll be keeping this eyepiece for a long time. Yes, it's a single fork-arm mount, means fewer counterweights and no need for meridian flips as long as the imaging train length isn't too long (although I do meridian flips anyway as my imaging train is at risk of colliding!). It's a great mount! Tracking is great as long as there aren't wind gusts blowing about. Haha, I did turn them off once I started imaging. To be fair, it probably helped with visualising Venus!

I initially did the collimation with the standard screws as I hadn't bought Bob's Knobs by that time. Since it held collimation so well, I've decided to leave things as they are despite having bought the knobs; if collimation goes off then I'll install them. I'll see what the stacking is like, but these initial results with the 0.7x reducer are very promising despite the spacing discrepancy. At the moment my spacing is 135.2 mm vs a requirement of 106 mm (105 + 1/3 of my filter thickness which is 1 mm). I'm not sure whether the Esatto's thickness counts fully here, as the SCT adapter slots flush into the back of the focuser body, and the reducer screws fully into the adapter which may actually reduce the overall spacing. It certainly won't reduce spacing by 30 mm, but I wonder if this is a factor.

Not looking bad at all! Just some lines through stars at the bottom (from an overhead cable).

I asked Primaluce Lab this exact question, and the reply was "In the EdgeHD design, the reducer has to be threaded to the telescope back cell and the distance from the internal field flattener to the reducer has to be fixed."

I must sound like I'm being paid by Primaluce Lab to promote the Esatto, but it really has made imaging so much easier. I'm doubting whether the excess spacing with the OAG will result in any success to be honest, but summer is for experimenting!

Decided to try my hand at long FL imaging again and to do some equipment testing using my Edge HD 8 with an Atik 490EX sitting on an Avalon M-Uno. What better time to try out galactic imaging than when the moon is almost full (!) The Avalon guided beautifully throughout the night, hitting a lowest RMS of 0.36 which I'm very pleased with considering I set up and tear down every time. The equipment seems to be working together nicely. Star shapes aren't great as seeing wasn't the best, but I'm fairly happy with it for now. I've tried to hold back with the processing due to the data not being of the greatest quality, hopefully can improve this with more RGB and Lum data. Prior to imaging, I attached a star diagonal with a Baader 8-24 mm zoom and did some observing of Venus and the Moon, was completely blown away by the detail I could see. Just incredible! Atik 490EX Atik EFW2 Chroma RGB filters Atik OAG Primaluce Lab Esatto 2” Robotic Focuser Celestron Edge HD 8 @ FL 2032 mm Avalon M-Uno Pegasus Ultimate Powerbox Intel NUC Mini PC Dark, flat, bias frames and bad pixel map applied Integration in AstroPixelProcessor, processing in Pixinsight Bortle 5 skies Lunar illumination – 97.5% R: 60x60s (2x2 binning) G: 60x60s (2x2 binning) B: 60x60s (2x2 binning)

No worries. It was the CHL version, yes. I have to stress that this is only my experience with these focusers, I'm sure others have had different results. With the Esatto, I have my Atik 490EX, Atik EFW2, Atik OAG, M54-M54 male-male adapter, F54-F56 adapter screwed directly into the focuser drawtube (it has M56 male threads). This is without the reducer in the train. With the reducer if things work out, I'll continue to use the OAG. If no luck I'll try a guidescope, as without the OAG I can get the spacing perfect. With the Moonlite CHL I had a QHY163M, QHYCFW2, QHY OAG-M. This was attached to a nosepiece which was inserted into the drawtube.

Agreed about the add-on trend, but I've become a fan due to the quality of their items. The Esatto was pretty much plug and play from the start and I've had zero issues with it. With my FSQ85, the stock focuser was just rubbish and I tried a Lakeside motor with it. Every other time it would either slip or tilt, causing my image to shift significantly. Same issues with the Feathertouch. No matter how tight I made the system there was always image shift. I tried the Moonlite with the Edge HD 8, same issues with image shift/tilt. Since I've had the Esatto I've wasted no time with focusing at all, it just works away in the background. Zero image shift. I'm sure people are working successfully with the Feathertouch and Moonlite setups and maybe I just got unlucky, but I'll be sticking with the Esatto for now! I'm not sure how much of a rush you are in to buy a focuser, but I can do some testing with the Esatto and 0.7x reducer at 135 mm spacing and let you know how it works out (although forecast is cloudy for the foreseeable future!).

I have 2 Esattos for my Edge HD 8 and FSQ85 and can't fault them in any way; autofocusing is now a breeze with zero slippage and accurate results. The only issue is that the focuser is 67 mm in length, and so that leaves you with only 38 mm to play with if you're using the reducer. I find that with an OAG I'm well over the spacing, so I'm imaging at F10 at the moment (which I'm actually liking!); I spoke to Primaluce Lab about it, and they said that another customer had a similar issue but managed with the reducer and is getting good results despite the spacing being off by approx. 25 mm. I don't know how much I trust that to be honest, so I'll attempt to use the OAG with the spacing as it is, and then use a guidescope if that doesn't work out. My gear at the moment: Atik 490EX + Atik EFW2 + Atik OAG + M54-M54 male-male adapter + F54-F56 adapter. The F56 adapter screws directly into the Esatto's drawtube, so at the moment the whole imaging train is screwed in (with the exception of the dovetail connection between the 490EX and EFW2 which is easy to adjust) with minimal potential for tilt. The Esatto is £510, the scope-side adapter is £30 and the camera side adapter is £80, so a total of £620 from FLO. My issue with focusers where the motor is attached to the focuser shaft is that there's a very real potential for slippage, and this can come into play any time and ruin a perfectly good imaging session. I've had this issue with the Moonlite and Feathertouch focusers, which is when I gave up and bought the Esatto. No issues since! PM me if you need any more details.

Dithering for me was a game-changer with my 1600MM-Cool. It was prone to getting significant fixed pattern noise, and dithering completely eliminates this once you've done the stacking. As a rule of thumb, I would dither every 5% of frames e.g. if I was taking 100 subs I would dither every 5 subs. Again, this is a general guide I found online, and I ended up experimenting to minimise dithering whilst still getting a benefit from it (as it does add time to imaging). I've long since sold my 1600MM-Cool and moved over to an Atik 490EX, and I found that dithering less often works well with the Atik.

I've been using the 3" and I can't fault it. Connects without any issues and the movement is incredibly precise. I'm about to get the 2" version for my SCT! Just make sure they have the correct adapter for it.

Thanks, I was sure I had it right! Having done some further imaging, I think it may be a case of tilt. I'll keep adjusting parameters and seeing where it takes me I guess!

Hi all, I've been fighting a losing battle with figuring out spacing between my Atik 490EX and the Takahashi 0.73x reducer. I have an FSQ85-EDX and am using the 0.73x reducer with it. The reducer requires a spacing of 72.2 mm, plus 1 mm added to it to compensate for 1/3 of my filter thickness, giving a total of 73.2 mm. My imaging train and measurements from camera to reducer are as follow: 490EX backfocus 13 mm + Atik EFW2 22mm + Atik OAG 24 mm + M54 male-male adapter 2 mm + M54 5 mm extender + Tak CA35 adapter 7.2 mm = 73.2 mm. This gives me a radial star pattern which indicates that the distance is too much (first set of images below with corners). The issue is that I had previously tried this without the 5 mm extender as I had left it out by mistake (which would give me a spacing of 68.2 mm). This still gives me a radial pattern which indicates that the spacing is still too much (second set of images), which doesn't make any sense as the spacing is actually less than optimal! Exposures are 300 seconds in H-alpha. Any guidance would be appreciated, as I'm pretty close to just giving up on the reducer and going with the native FL. Spacing 73.2 mm Spacing 68.2 mm

Last-minute overthinking got the better of me, and I ended up buying Nikon Action 12x50 EXs as Amazon had knocked about £70 off an open-box product. Seem to have good all-round reviews, are nitrogen-purged with aspherical lenses to minimise distortion. Will post some images of the bins once I've received them. You never know, they might just be enough to satisfy both backyard and travel viewing, so may never end up buying 25x100s!