centroid

Astroart 8

I successfully imaged for 12 years with SX CCD cameras. See examples here: https://davesimaging.wixsite.com/mysite I now have a 294c CMOS based camera, and if I demosaic (debayer) a single image (sub), I get colour, nowhere near as accurate as with CCD, but that is adjustable. However, the problem is, if I align and 'stack' (sum) a batch of images, I get a mono result, which won't debayer to an RGB image. Almost certainly me doing something wrong somewhere, but It has me mystified. Also, if I take a single de-bayered colour image into photoshop, it appears as a mono (greyscale) image, albeit, in Astroart it appears in colour. I'm not sure what the white Like/Answer/Share box is below, not seen that on the forum before? Like Answer Share

I could have done that, but he didn't have it in stock, nor did anyone else in the UK. As such, I ordered it direct from TS optics in Germany, snd it will be here via UPS, on Tuesday.

The "calculated" distance setting on the flattener, taking into account the added width of the M68 to M63 adapter will introduce, is a theoretical l.5mm. Until the adapter arrives from Germany, any experimenting will have to wait, then of course the need of a clear night. If I get it working, I will post a picture for you. I will also feed back my findings to FLO, as requested.

No its definitely a fixed M68 attachment Alex. The M68 male to M63 female, is a bit of an oddity, and quite uncommon. M68 female to M63 male is readily available. It seems the only option is from TS Optics in Germany: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p6692_TS-Optics-M68-System-Adapter-von-M68-auf-M63---Riccardi-Anschlussadapter.html No stock anywhere in the UK, and although FLO offered to order one in from TS, in the interest of expedience, I have ordered direct from TS. I'll get there in the end 😅

It seems that I'm really not meant to use this flattener 🙄 Having received the flattener, promptly from FLO, I found that I needed an M48 to M42 adapter to attach the camera, so I ordered one from FL, which again came very promptly. This morning I went to fit the flattener to the scope, only to find that the focuser tube has a female M68 thread, and not the more usual M63. The flattener is M63 male. So I need an M68 male to M63 female adapter. Not a common adapter, whereas the reverse gender is. It looks like it is a TS Optics item, and quite expensive for what it is too, but needs must I guess, and unfortunately, not a FLO stock item.

An interesting off-forums conversation with another user of the same brand of 294 that I have, reported an issue of vibration from the fan, during long exposures, giving rise to rice shaped stars. Apparently, easily mistaken for coma. He proved this by removing the DC power, and running on the USB alone, thus no fan, and the problem disappears. Reconnect the DC power, fan runs, and problem reappears. He says that he has seen other reports of this? Hopefully, with the new WO flattener/0.8x reducer inline, which will bring my 115mm f/7 scope down from 805mm FL to 644mm, and f/5.6, I'll not be needing long exposures with the sensitivity of the 294 sensor. This should also reduce the amp glow issue. I have to say, moving from CCD cameras to CMOS, has been a whole new experience. 😉

So it can be done then 🙂. Seems that ZWO can eliminate the top and bottom 294 amp glow, but Touptek can't, or don't bother. However it seems that it can be calibrated out from the light frames, so a problem solved it would seem, and I guess I am going to find out.

A nice thought Vlaiv, but we don't get enough of the clear, crisp winter nights that I enjoyed , back in my previous imaging days, (at least in my part of the UK), so LRGB imaging is no longer the option for me, that it once was. I'm not qualified to say whether it is down to global warming or not, but we seem to have milder winters that are plagued with cloud, so for me, OSC now makes sense. I used LRGB imaging for quite a few years, with an SXVR H9 and then an SXVR H16. Excellent cameras, UK made, and excellent customer support. SX ccd cameras are still available, but as astro imaging is now a secondary interest to my photography, I must resist the temptation to buy one. 🙂

Indeed it does Martin. No top and bottom amp glow, which confirms what was reported on the other forum. Same sensor, different hardware/electronics design.

It seems that they all have their individual quirks Vlaiv, being the "nature of the beast" I guess. Cheaper than CCD of course, but there is no such thing as a "free lunch" 🙂 I note the dark frame from Budgie's ZWO 294 does not display the top and bottom amp glow that my brand of 294c camera does. How nice the CCD days were, no starburst, minimal amp glow, and no gain or black level settings to be concerned with. Unfortunately, less sensitive than today's CMOS sensors, and , more expensive. I guess Starlight Xpress, ATIK, and others, will eventually have to move to CMOS.

I expected to see 'starburst' Vlaiv, as its inherent with the sensor, but not the 'glow' top and bottom. On another forum, dedicated to the brand of camera that I am using (I will not mention the brand, as the Admin there are very sensitive to any comments that might be seen a negative to their products, even if factual), one member commented that he had the opportunity to compare this camera with a 294c based camera of another brand. He found the 'starburst' was exactly the same, but the top and bottom glow was not present. I wonder if anyone here, would like to confirm that they either get this top and bottom glow with the CMOS camera, or not.

I have been building a Darks library for my 294c Pro TEC. Given the 12 years of imaging I spent with CCD Cameras, CMOS 'Starburst' is something new to me, but expected. Attached is a 240s Dark, taken at -10 degrees. Apart from the 'Starburst', am I also seeing 'Amp Glow; at the top and bottom of the image?. The image is cropped for posting, and ' stretched' for visibility.

Thank you David, much appreciated 🙂

Would you believe it 🙄. The WO flattener/reducer arrived very promptly from FLO, and the rarity of a clear sky forecast for tonight. I now realise that I should have ordered an M48 to M42 adapter to go with it , which I have now ordered. Ah well, the next clear night then, whenever that will be.

As a follow on from my Field Flattener/Reducer post, I now have the above optic, and very nicely made it is too. The Flattener is adjustable, and has a numeric adjustment scale on the barrel. WO publish a set of adjustment settings for some of their telescopes, but that's as far as it goes. There is no indication as to what the numbers represent. After an extensive trawl of the internet, I found a post on an American forum, where it was quoted that the numbers represent distances in mm, from the rear element to the rear shoulder of the flattener. For example, a setting on the scale of 5, represents a pre-set back focus of 5 mm. Therefore, if this is true, then with my 115 and 294c camera, the back focus setup would be as follow. Required back focus distance = 55mm (pretty much standard). Front of camera to its sensor is 17.5mm, leaving 37.5mm of spacing to find. A 20mm + 15mm spacer gives me 35mm, leaving another 2.5mm to find. If the numbers on the flattener do represent mm distances in mm from the rear element to the rear shoulder , then a setting of 2.5 on the scale, should give me the required 55mm of required back focus distance, with a bit of "wiggle room" either side. Well that is the theory anyway, and a live test will prove or disprove it. It would be nice had WO explained just what the numbers on the scale represent. From my searches, it seems to be a question asked many times, but one that could be simply answered by WO informing the customer as to what the numbers represent. Maybe I'm thinking too logically 😉

Ordered from FLO yesterday, and arrived this morning 🙂 It certainly looks, and feels like WO quality, as I remember it. No clear skies here this weekend, or in the forecast ☹️

It does look good Vlaiv, but it would have been a £360 gamble, which made me decide otherwise, albeit it might well have been fine. If the WO unit matches well, and produces a good result, then I will be more than happy. I have had WO gear in the past, and was happy with the optical performance. Its nice being able to try the WO optic on my setup, in the knowledge that if it doesn't perform, I can return it, thanks to FLO's excellent customer support policy. That said, I am fairly confident that it will do the job, and produce the desired result. According to Mark Ludes, the APM CEO, the Planostar is a "Chinese" copy of their Ricarrdi design. The Altair Planostar was the obvious choice, as it is matched to my scope, and guaranteed as such. However, there is no stock in the UK, or in Europe, and nobody can predict when there will be.

I looked the Ricarrdi, which was in stock at APM in Germany, but could not be 100% sure that it would be a good match for the Altair 115 ED Triplet and 294c combination. Non dedicated flatteners, can be problematical, either working well, or not so well. The Ricarrdi would have been an expensive experiment if it was not suitable, as probably not returnable. The Altair/Planostar is designed, and guaranteed to match the 115, but is out of stock, with no availability date in sight. Apparently there is a shortage of ED glass. So, it was back to tried and trusted FLO to see what options they had. Although the Altair 115/294c combo is an untested set up with a WO Flattener, a WO option was suggested. Given FLO's 30 day returns policy, and following helpful discussions with Dave, and Grant at FLO, I have ordered the WO unit. Having looked at the back spacing requirements etc, I am fairly confident it will do the job nicely. 🙂 From back in my earlier imaging days (pre 2014), it was nice to find that upon my return to Astro imaging, FLO's customer service/support is still as good, as it always was.👍 I will of course feed back my finding to FLO. https://www.firstlightoptics.com/reducersflatteners/william-optics-adjustable-flat6a-iii-08x-reducer-flattener.html

Thanks Vlaiv, another option to consider.

This has been recommended as a good match for the 115. The only problem is it would seem that there is a six week supply delay, so I will have to look at alternatives. https://www.altairastro.com/planostar-08x-reducer-for-altair-115ed-triplet-refractor-with-m63-25-focuser-9187-p.asp?fbclid=IwAR1js2MvWYcM0LG1llFyjbTaJ8ekEBG7amt6OejMjgcYO4-Mv2EYvOA45dM

Thanks Ian, I will look at that option. It does seem quite cheap for an optic? Having spent £1200 on a scope, the optics of which have proved to be very good, I am a bit wary of putting cheap glass in- line. But maybe the optical qualtity is fine. A bit like when I spent over £3k on a 5d MklV, I have only ever used L series lenses with it.

I have an Altair Starwave 115 f/7 ED Triplet, and 294c Pro Tec camera. I find that I am getting coma, almost certainly due to the 17.47 x 12.86 size sensor. Not bad, but enough to want it gone. As such I need field flattener (coma corrector), and it would be useful to combine this with a 0.8x Focal Reducer. What, if any, are you using, with a similar camera/scope combination.

Just my personal experience of course, but in 12 years of asro imaging (pre 2014), I had several SX camera, and with the exception of a light leak into the SXVR H16, they were 100% reliable. Terry at SX always provided excellent technical support, and also sorted the light leak very promptly. When I wanted my H9-C converted to mono, he did it for the cost of the CCD. Having returned to imaging after an 8 year hiatus, CCD is now very much yesterday's technology, with CMOS now being the in-thing. Albeit we have to concern ourselves with establishing and setting the correct gain, and black point, something that was not necessary with the CCD cameras. If SX were to move to CMOS, I wouldn't have to think twice about going back to SX. That said, as yet, I have no complaints with the Altair 294c Pro Tec, but in fairness, it is early days yet.

Altair Astro. I have the Altair Hypercam 294c Pro Tec. It does "what it says on the tin", and hasn't let me down yet. Chinese made of course.