tomato

Thanks for all of the replies and suggestions, looks like I have a way forward. I can certainly measure the distance between the ends of the two hooks to obtain a scale factor, I don't have PS but there is a resize function in APP and Affinity Photo. AP also has an image align function. When I have @Tomatobro's RC data, we'll give it go.👍

I’m attempting to combine data on M31 from 3 different scope/camera setups, a RASA8/QHY268c, Esprit150/RC571c and an Altair102APO/ASI178mono. The first two have been straightforward with plenty of background stars available, however the third set up has imaged the core of the galaxy, principally to get detail on the dust ‘hooks’ that project into the core, and so by nature of the small FOV, there are very few discrete stars in the image. I’m still collecting a full set of LRGB data, but all initial attempts to combine this data have failed, with APP unable to register the stack with the other two, despite trying a range of different settings. My collaborator on this project, @Tomatobro, has collected a full set of data using his RC10/ASI1600 which is better than mine but I suspect I will have a similar problem. Any thoughts or ideas on this? One solution would be to do a mosaic so some background stars are in the FOV, but I wondered was there anything in Pixinsight’s vast array of tools for this. I suppose I could manually align, but the data still needs to be resized to match the other images, and how would you do this?

That's a fine first go at M31. Although it is a popular first time DSO to image (like M42) I find it a tricky one to process when you have to balance the bright core with the fainter outer regions. Although the background is nicer on the later versions, I think some of the fainter outer region detail has been lost. Have a look at the Left hand side of the histogram peak to see if you have any space before the peak starts to appear.

Here is another version where I have tried to improve the stars a little bit.

I doubt it, the star shapes aren’t great in the RASA raw data, so there has again been a lot of processing to correct these, which has no doubt created artefacts. I pushed the settings in NoiseXterminator to improve the galaxy detail, but there is always a trade off.

Thanks for the feedback. I have a custom made adapter which allows a 2” filter to be screwed in, and employs the tapered adapter for the QHY camera. I’m currently experimenting with home made semi circular shims and do all my adjustments on the scope, but I will look at making a test jig.

Excellent M31, the dust lane detail is superb.

Thanks for your comments, much appreciated. The background could be clipped, the majority of the stretching was done in StarTools and that can result in a clipped background if you are not careful. I will have another go in PI. I forgot to mention I downsampled in ST by a factor of 0.35, the original was 163M pixels...

Just got these before a cloud bank came over, RASA8/QHY268c, 10 sec exp, Gain 30, offset 30, cables arranged in a circle. There is a light house effect on the star but not sure if this is cable diffraction. Still some tilt on my sensor I'm afraid. 2022-08-31_21-33-02__-10.00_10.00s_0000.fits2022-08-31_21-37-44__-10.00_10.00s_0000.fits2022-08-31_21-41-13__-10.00_10.00s_0000.fits

This is my second go at M31 since Astro darkness has returned, a combination of 139 x 2 mins with the RASA8/QHY268c and 125 x 2 mins with the Esprit 150/RC571c. Calibrated, stacked and combined in APP, processed in StarTools, PI and AP. There is another set of data still to add, "high res" on the core, but that is being captured with good old LRGB, so it's not finished yet. @Tomatobro is collecting data on the same region with his SL RC10, and his subs look superior to mine so that's what will go in the mix when all the channels have been collected. Thanks for looking

Wonderful image. It’s intriguing (to me) how the dust and voids seem to follow an even distribution, i.e. you don’t get a big area of sky completely covered in dust, then a big clear patch, but rather channels of each. I dare say there is a sound cosmological explanation for it which I have failed to pick up.

Apologies Alan, for not responding to your request. I’ve been dealing with a serious tilt problem on my RASA8 which I think I have now resolved. So if it’s clear tonight I’ll point it at Deneb and take some subs before I start my imaging run. Steve

For owners of the QHY268c, here is a crude but effective method to adjust tilt on the camera. I usually rely on adjusting the three screws on the camera ‘wedge’ but after 90 minutes of backwards and forwards from laptop to camera, I thought there must be an easier way. The tilt was all on one side on the short side of the sensor, so maybe a semi-circular shim of the correct thickness placed under the ridge of the adapter on the appropriate side would work. The only material lying around that would do the job was clear acetate, so I cut out two shims of 0.06mm and 0.3mm thickness. I put the thicker shim in first, but the tilt was worse, so I swapped it to the other side of the holder and voila! the tilt was almost eliminated, see before and after cropped images. The camera is held in place by the lateral screws, so hopefully by not being under great compression the shim material will not flow too much and the tilt will not return, but time will tell. Not the most precise and elegantly engineered solution I’ll grant you, but cheap and quick, and reduces my embarrassment somewhat when folks pixel peep my RASA images.

Yes, they do look like a line of tanks rolling off the production line. I think the photo is shouting “Look! We’ve made more than one!”

If all those grey bits are machined from aluminium billets, (I can’t see any welds), then it is indeed very competitively priced.

Yeah, a significant tilt on the camera, so lots of processing involved to improve their shape, and who knows what the Win 10 Napa filter did to them?

Looking at the photos, are the housings/pillar mountings made of 3d printed plastic? I would be fine with this approach for a Star Adventurer class of mount, not so sure if hanging 50 kg of astro kit off it.

@Tomatobro made a very sensitive load gauge to help me balance my heavily loaded Mesu 200. I could certainly get it much closer than just feeling the drag on the drives. As Olly said, the Mk 2 can disconnect the drive but respect to Lucas to develop an engagement/disengagement mechanism that delivers the correct amount of thrust repeatedly each time.

I think there is a distinction to be made between multiple scopes using the same imaging scale and those with differing scales. My dual Esprit 150 rig required a number of engineering modifications, principally an adjustable bracing plate across the two scopes, to work successfully with an OAG. However, currently I have paired it with a RASA8 with a more forgiving image scale and this is working fine without the bracing plate. Mesu 200s certainly at lower payloads are quite tolerant on balancing, but it gets more critical as the load goes up. I do enjoy creating and then trying to tame a monster.👹

Yes, a must have for Project Apollo fans. I see the author used AP processing techniques to get the best out of the raw stock, how appropriate! I’ll suggest it as a Christmas/birthday present.

I think Project Orion was great, imagine a huge spacecraft being pushed along by successive nuclear detonations from bombs dropped through a shock absorbed pressure plate just bonkers…

I’ve not taken mine apart but I believe the drive is transferred through hardened steel rollers and disks, no rubber involved. Some Mesu mounts have been operational now for 10+ years at sites that get more than a handful of clear nights every month, mine is now 8 years old and is performing as well now as when it was new.

I briefly considered deleting my raw data after it had been successfully calibrated and stacked, but after thinking about the effort that went into acquiring them, plus the ever evolving data processing software, meaning it could be revisited in the future, I decided buying some more data storage was a worthwhile option.

Clearly a good strong concrete mix.

With a camera attached to the telescope I think it’s fair to say you will see a brighter, more detailed and colourful image than just using an eyepiece alone, simply because it has the ability to collect and present more signal to the eye. These days there are electronically enhanced eyepieces which give stunning views at the telescope, but they can be very expensive. However, I’m sure the visual only enthusiasts will say that the experience is not matched by viewing directly at the eyepiece, seeing the object unadulterated and without digital enhancement. Of course any view through a telescope is enhanced, either optically or electronically or both, so in the end it’s a personal choice.