RyanParle

Hi All I had planned on capturing a new set of Flats today using CCD Commander's Automatic Flats capture but I've lost my previous settings for it and I'm trying to remember the behaviour of the ADU target. The camera is an EOS 50d which has a 14bit ADU and my image capture is Maxim DL which uses 32bit floating point. Should I set my target ADU in CCD Commander based on the native ADU of the camera or based on the 32bit values in maxim dl? If its based on the camera native ADU values I have no problem in doing the maths to get the right value but I wouldn't know where to start if the target ADU is based on the 32bit floating point system. Can anyone offer any advice on this?

I have the pickup prism as close to the main sensor as possible without causing too much vignetting and everything has been inspected and is meticulously clean. Although this afternoon i noticed that tightening the lock screw for the OAG focus position causes the guider to tilt, it looks like the lock screw was grabbing the stalk so I have rounded the tip of the screw, everything seems to snug up nice and square now and daylight images seem sharper so I will try it out when its next clear. I have noticed that the image from the QHY5 is very noisy which makes me wonder if that is adding to the issue preventing Maxim DL from finding a guide star. I looked in to trying my old Atik 16IC-S Camera which is more sensitive but has slower image download, but unfortunately due to its rather large diameter it fouls on the backplate of the telescope. I must admit that i keep forgetting to save images, Next time I'm set up I will make sure to grab some.

I think @astrosathya was saying he was concerned that rotating his camera / oag might upset the balance of the scope.

I hate to bump a thread but this issue is driving me mad, anyone got any ideas?

That looks like "The Sky 6" to me

Yeah, I gather the cables will fit, but the compatibility depends on the hardware used in the usb3 hub inside the upbv2. Some USB 3 hubs are backwards compatible on the upstream port and some aren't. The USB 3 hub in my pc monitor is not backwards compatible and simply doesn't work with a USB 2 cable. It will however work with a usb3 cable plugged into a USB 2 port. [Edit]. I have just had a reply from Pegasus Astro who informed me that all ports are fully backwards compatible with USB2. So for now whilst all of my cameras are USB2 I don't need to worry about getting a long enough USB3 solution.

Yeah I think the Pegasus is going to take my money! I think i'll also have to come up with an alternative mounting solution, I will need to remove the unit from the top dovetail of my telescope in order to fit it back in its flight case, I'm sure i could fabricate something up pretty easily. I expect I will end up investing in a USB 3 over Ethernet solution for the data cable, Generally I run a cable out from the laptop to the telescope. I'd like to still be able to do this. Do you know if you can use a USB 2 cable between the Computer and the hub if you don't need USB3 speeds?

That looks like it has potential, however it would require that I set up another camera and optics as neither the FOV from my Guider or Imager are anywhere near the requirements. but thats not out of the question. that would be great if there was a wider choice of compatible cameras, I've also heard of people flashing certain QHY5 ii models with the Polemaster firmware to avoid hacking the software.

Does anyone know if anyone has had a go at a DIY Polar alignment camera similar to the setup used for the Polemaster? It looks like a simple thing to do from a hardware perspective, not much more than a camera with a lens and then some kind of bracket to install it on the mount. I wouldn't know where to start on the software side of things but it doesn't seem a particularly difficult thing to achieve?

I've used a TS 9mm OAG with an old QHY5 guide camera on an 80mm APO for many years with great success, I nearly always fond a good guide star no matter where I was pointing the scope. I actually have an instrument rotator on that scope which was intended to ensure I always framed my image to give a good guide star, I didnt really need to use it for that purpose and in the end i just used it to frame my main image sensor. I actually found having an OAG setup was quicker to set up than a seperate guide scope, the OAG and Guide cam stayed attached to the scope, all i had to do was attach my DSLR to the bayonet and i was ready to go.

Run the images through CCD Inspector, It looks to me like colimation or focal plane alignment. I saw the same thing when I tested my RH200AT for the first time. CCD inspector made it super easy to fine tune it all in.

Hi all I am having some issues in setting up an OAG on my Officina Stellare Veloce RH200 Astrograph, I had hoped that it would be a straight swap from my APO as the camera configuration was staying the same. however i found that i did not have sufficient back focus and had to remove around 13mm of spacing from between both cameras and the OAG, as a result the focus position of the guide camera was lost, I assumed that setting it would be as easy as when i set it all up on my 80mm APO... well we all know what they say about assumptions. 🤣 Instead of seeing the out of focus image of a star as the usual ring shape, i found there were two arc shapes which appeared to converge as the focus point was reached leaving a kind of elongated "X" Shape. As a sanity check to see if i was near focus i decided to aim the guide camera at the moon, I found the image was a little soft but still pretty close to focus.but the strangest thing was a dark pillar that extended about 1/2 way up from the bottom to the centre of the image, It looked like there was some physical obstruction away from the focal plane. However inspection has found no evidence of any such obstruction. I then got to thinking about the optical path and the behaviour of the light along it. First off a description of my optics / Imaging train, The Astrograph has an aperture of 200mm and a focal length of 600mm, the focal plane is 60mm beyond the focuser being fully wound in and the field is supposed to be "sub micron" flat up to 51mm diameter. The Main imaging camera is an EOS 50d (back focus 44mm) which is fitted with the Teleskop Service 9mm OAG using the direct EOS mounting ring option. The OAG is configured so that the pickup prism is as close to the centre as possible without casting a vignette on to the main sensor. I've measured this to be about 12-14mm from the centre of the optical axis. Connecting the OAG to the focuser is a 2" shoulder-less nose piece which allows the OAG to butt right up against the drawtube, We start at the focal plane where a sharp in focus star converges to a point that is around 8 micron diameter (around 2 pixels on my EOS 50d) If i then move my focuser by 1mm the ring produced by the out of focus star is approx 100 pixels in diameter (this equates to about 0.5mm diameter on the sensor) when you project the spread of the light cone out to 50mm forward of the focal plane (which is approximately where the prism lies) the ring of light works out to be a diameter of around 24mm. Now the prism of the OAG is 6mm x 10mm which means that only a section of the 24mm ring will fall on its surface therefore projecting an arc back towards the focal plane, does this seem like a reasonable explanation as to what is happening here? although i am not sure how this could cause the 2 arcs to converge in an X shape or even how it could cause the dark "pillar" on the image of the moon. Does anyone have any advice as to setting up an OAG on a fast compound astrograph like this? I had imagined that OAG would be easy as there is tonnes more light coming in compared to the 80mm APO which incidentally never failed to find a guide star. I would like to have had the foresight to save some of the images from the guide camera but alas i didnt think about it until afterwards. I'll try again tonight if its clear.

Hi all I'm looking in to some bit of kit that can help consolidate the extensive amount of cables and control modules that I am running out of places to stick to my mount. I'll be wanting a minimum of 4 USB ports must have at least one USB3 for a future camera upgrade. Power for Dew heater, Flat panel, DSLR, Mount & a few spare for alternate cameras. Stepper motor focus control, Ideally with temp compensation. There are a few units that I have seen and i'll list the Pros & Cons of each considering my setup requirements. HitecAstro Mount Hub Pro Compact. Pro's: Power, dew heater & focuser control Con's: USB hub would be nice. Doesn't seem to have temperature compensation for focuser. HitecAstro Mount Hub Pro V4. Pro's : As above but has USB Hub, focuser temperature compensation, Power monitor & Electronic Fusing. Con's: Quite a lot of money compared to the above unit. Pegasus ULTIMATE PowerBox V2. Pro's: pretty much the same as the Hitec Hub Pro v4, Also has humidity sensor for auto dew heater control Con's: still a little pricey. Primaluce Lab Eagle 3 series (not interested in core model). Pro's: Plenty of Power & USB options as well as manual control of dew heaters etc. Built in computer functionality is a really nice touch but not required. Con's: Lacking focus control, Price for the base model is reasonable, but i'd want the top line one as a form of future proofing. Final option is DIY. Pro's: Can be designed to suit my requirements exactly, Possibly the cheapest. Con's: Lots of effort to design all the elements software etc. like many of my DIY projects it will probably end up half finished... FEATURE CREEP!!! What other options are there on the market? I have seen the Lunatico / seletek products but they don't really appeal to me. At the moment I'm thinking that the Pegasus unit is the best value although the Eagle 3 would win it hands down if it included a focus controller.

Ok that is worth keeping in mind, The backplate has Tilt/Tip adjustment, but I guess that if the sensor is mounted slightly of plane rotating the camera would negate these adjusters. Initially I was thinking of having the rotator to ensure a good guide star could be found but with such a fast optical train i suppose it probably wont be an issue, however it would still be nice to frame objects nicely on the sensor. I currently have the scope in my possession so will experiment without a rotator and see how critical the rotation of the camera is... that is of course if we get a clear night. I would still like to find something that will fit if possible.

Hi all, I am in the middle of striking a deal on an Officina Stellare RH200 Astrograph, provided that the deal goes ahead i'd like to have an instrument rotator and motor focus. so I am looking for a rotator and focuser (either combined or separate low profile units) that will fit my application. so far I've not found anything. here are the constraints I have regarding backfocus etc. Astrograph backfocus: 105mm (from backplate) Camera backfocus: 44mm + OAG: 9mm = 53mm This leaves 52mm to somehow squeeze a rotator and focuser in to, then taking into account that I will need a few mm each side of the focal plane its probably safe to say that the thickness of the rotator and focuser (fully in) should be no more than 50mm. The Standard focuser is 40mm -55mm so doesn't leave room for any additions in the focal train. Can anyone suggest any kit that would fit in the space i have available?

After a few months of being busy on any possible clear night I finally had a couple of nights where I could get some 5min dithered subs. Things went pretty well and I got 4 hours worth of data each night which when stacked looked very clean but lacked in depth compared with the long exposures, but when combined with the previous data actually turned out looking better than expected although this time I have struggled to get the colour balance right, its all a little too yellow, & I cannot seem to get the blues to show, also the background is still a little noisy which I put down to the noise from the older data but I think its a big improvement on before. I'm still not sure my results are great considering that there is around 18 hours of subs. Anyway here is the latest image, comments and critique welcome.

From the Maxim Dl Manual: Sigma Clip – a compromise between Average and Median. A standard deviation is calculated for each pixel location, and a standard deviation calculated. The pixel with the largest deviation is rejected if it falls outside Sigma Factor times the standard deviation are rejected. The average is then taken of the remaining pixels. SD Mask – a custom variation on Sigma Clip contributed by Ray Gralak. This is an iterative algorithm that more effectively removes outlier pixels while preserving "good" pixels. It is most useful when the number of images available is too small for effective use of Sigma Clip. There are a few settings that go with Sigma Clip & SD Mask, I've not experimented much with them but when I have I've never noticed much difference. I will of course post some dithering tests when I get the opertunity to get some more data, the weather looks good for next weekend so fingers crossed!

So after rebuilding my calibration library I haven't noticed much difference to before, but I've taken the time to make a comparison between SD Mask & Sigma Clip as well as Dark, Flat & Bias vs Flat & Bias Each of the images have exactly the same screen stretch, I think that the Dark_Bias_Flat_SD_Mask file is the cleanest of them all but maybe slightly lacking in the fainter areas. the background noise in the Bias_Flat_SD_Mask file appears a lot less even, I guess this is where the dithering will help out. Sigma Clip seems very noisy by comparison to SD Mask, again I assume that dithering would help here.

OK, Have just run a stack with calibration turned off, and whilst it was a bit messy due to the lack of flats it looked like there was a lot more information above the level of the background noise, so I'm thinking that I have a bad set of calibration masters. I'm currently going through "set calibration" and sorting some settings, some how my default combine when creating master calibration frames had become set to Sigma Clip, and Add pedestal was set to 0. I've now set the combine to average for flats & darks (should i need them in future) and Median for Flats. I've also set a more realistic pedestal value of 3x BG noise level. Maxim is currently creating my Calibration master frames, once it has done I'll try another stack to see if its any better.

I've just checked everything through and it appears that it is correct, i'm not sure why MaximDL has saved those integration times to the fits header, but they are definitely the stacks, I've posted a single 15 min sub as well for reference (It has not been de-bayered yet). The file name is messed up as I had an issue and restarted my CCDC script part way through, this for some reason stopped the "object info" being written to the filename & fits header, i manually updated the Fits header but didnt get around to the file name. _900s_270.0deg_20190411_0048_000000720.RAW.FIT

Ok i'll give it a go tonight if it clears up enough... theres a little bit of a haze out at the moment! Fingers Crossed! Should be able to get 90 x 5 min subs easy enough I've set a Minimum dither of 15 px And a max dither range of 100px hopefuly that should smooth out the background a little

Yeah, I understand why darks with a DSLR can be tricky due to the unregulated temperature, which is exactly why I built up such a big database in the hope that every image should have a matching dark somewhere (combined with Maxims dark scaling feature) I do dither when I image, i am currently using the default dither in CCD Commander which is a set to a mimimun of 1 px and a maximum of 4px how much dither would you recommend? Do you think you could pull out much more details than in my previous posted attempts?

After careful analysis of my .fits images and my .tif images I've concluded that i lost a lot of information in the conversion so i'm going to post the .fits files instead, you should be able to get more out of it this way. these .fits files are the combined RGB files, they will need splitting in to individual RGB files before running through FITS Liberator (or similar) Anyone got any good tips on getting the most out of FITS Liberator? I've also done an additional stack this time with SD Mask algorithm and no darks. I was pleasantly surprised at the quality of this stack so I'm beginning to believe that darks are less important than I first thought. this is posted here as well. M81 & M82_Bias_Flat_Dark_Sigma_clip.fit is the original stack M81 & M82_Bias_Flat_SD_Mask.fit is the latest stack M81 & M82_Bias_Flat_Dark_Sigma_clip.fit M81 & M82_Bias_Flat_SD_Mask.fit

Thanks Tooth_dr I would be telling a lie if I said that I was ecstatic with the image considering the amount of data I have, I thought that my local skies bortle 4 rating was mainly the reason I couldn't get more out of it. I will take the recommendation of larger dither & no darks, I'll try RE processing what I have without the darks to see if that gives better results, I think my dither is set to 2 px at the moment, what sort of dither amount would you recommend for future sessions? I will also try getting a lot more shorter subs on the next session. I'm also beginning to think that my choice of ISO setting could be an issue, is ISO 1600 too much for a 50d? I'm happy to post my stacked data for you and anyone else to have a go at, I'm sure there is much I can do to improve my processing and would love to improve. I am not able to post the data straight away but I'll add it when I am at the PC. The Veloce 200 Mkii has long been one of those "if money was no object" wish list items, but recently I was given an offer that was too good to turn down, the final deal is yet to be agreed but I'm expecting to pay around 1/4 of the trade price, it's all totally legit, no stolen or second quality gear. If all goes to plan then I should have it in my hands at the end of the year. The ED80 is a nice scope to use but the Veloce is so much faster & Sharper.

Ok so I've added in last nights data and got a bit more depth, I also sorted out the an issue I had with the flats not being applied when I calibrated the images, I think I've still got colour balance issues though, the dreaded pinky stars are back! anyway here it is, 23x 15min subs & 10x 30 min subs: Any comments welcome.