tomato

It’s a valid comment on the mount with the latest CMOS cameras but I wouldn’t go to the extreme and throw all your budget at the camera and scope at the expense of the mount. If your mount isn’t rated for the load you are putting on it, you will be throwing a lot of your subs away, even with short exposure CMOS imaging.

Just on the lens flexing issue, I went the budget option and purchased a SY135 with the Sony mount. The bespoke adapter is attached to the lens body by 3 original tiny screws and they could not cope with a Moravian G2-8300 hanging off it. A separate bracket was made that picks up off the lens clamp, this has eliminated flexing at this point.

I don’t think Patrick could have done the laconic pose on the rocky outcrop staring out into the sunset, Brian Cox has mastered that one.

Yes, I thought the Mesu was quite tolerant to imperfect balancing, but maybe not so forgiving when the payload is pushed. @Tomatobro is looking at ways of measuring the loads on the mount to achieve a more precise balance. With an OAG I have had guiding at around 0.5” RMS, but again with RA corrections all in the same direction, this is after using the Guiding Assistant settings in PHD.

Thanks for your advice but I cannot see this being an irreversible change. If you read the imbedded thread in the first post you will see I am following the method as provided by Lucas. If the revised tick number doesn’t work I can always revert back to the original setting. The giveaway is the RA is constantly correcting in the same direction and the guide points in PHD are well clustered but offset from the the centre in RA. I see this effect with two very different scope configurations on the mount (dual Esprit 150s, and RASA8/SY135 combination) so I don’t think it is balance related. I suppose I could try running it with just a guidescope centrally mounted on the Mesu, but that’s a lot of work, quicker to just give the tick adjustment a try. The mount performance is fine but if I can fix this error then I think it’s worth doing if nothing else it will cut down on corrections being sent to the RA motor.

Thanks for the tip, I have succeeded in measuring a star trail over 10 mins and have a value of 42.7 arc secs in 10 mins, 4.27 arc secs per minute. I was about to use the PHD Guiding assistant as a second measure but it has clouded over...😟

@newbie alert, you beat me to it, £10k is a fantastic budget, but will easily get swallowed up if you go for high end kit. I would still recommend the Mesu 200, that will future proof you for where ever you go with imaging, but I would like it to have some decent weather protection. Could you have a roll off sentry box over your pier?

Yes, it’s there, harder to observe visually no doubt, than capture on an image.

Great report, you got more clear sky than me on Monday night, but Shropshire is not a small county. The propeller is I think, the name given to the three radial dark rifts about 120 deg apart, visibly discernible in the cluster. In this image they are located at about 6 o’clock.

OK, will do. I also wonder about the effect of balance has on my guiding performance, particularly when I have in excess of 75 kg in total on the mount…

+1 for DisplayCAL, I use it with the Spyder 5 Express, in preference to the software bundled with the device.

Hi Peter, Thanks for this, if we get some clear sky soon I’ll try the star drift method, as I can directly see the effect on the guiding performance, but if the grey skies persist I will give your method a go. Steve

Thanks, next time I'll use a star that's due South, assuming I get another clear night this side of Christmas.

TBH I can’t remember if I had synced the mount or not prior to running the test. I think the scope was pointing at alpha Cass. I never measured the length of the star trail as it threw me when it didn’t run parallel to the horizontal axis of the image. I was going to adjust the camera to make it so but yes, you’ve guessed it, it went cloudy and has been so ever since.

I used a 8” F4 Schmidt Newtonian for AP back in the 80’s, which I still have, although it is very poor condition. The silicon sealant used to glue the secondary to the holder degraded over time causing the mirror to fall off and hit the primary.🥴 It was an absolute nightmare to collimate, I don’t think I ever got it properly accurate with those primitive adjustment screws. I might still restore it and see what it could do with a modern Astro camera on it. Note the attached F8 Newtonian manual guidescope, happy days!

Comes with a free poster, do you get one of those with Strictly Come Dancing on Ice?

For a while now, I have thought that the RA speed on my Mesu 200 was not at the correct setting to achieve optimum guiding. I found this very helpful thread on SGL and have attempted to follow the method to correct this: Mesu 200 RA Guide Speed Correction However, I have encountered an interesting observation when trying to implement the correction. I aligned the camera so that a star tracks along the line of the reticle cross hair on the image when moving in RA only. I have then let the mount track in RA for 10 minutes to measure the length of the star trail and so calculate the error in the speed. However, when I examined the image the star trails are not parallel to the reticle line, but at a small angle to it. This means the mount has moved both in RA and Dec, but how come this was not apparent when I did the test slew in RA? The only difference is the test slew was done at a much faster speed and for only 5 sec duration, vs the error measurement which was done at the sidereal rate for 10 minutes. Is this PA error or something else? Note I never get Orthogonal errors when PHD calibrates.

Yes, great value for money products, dare I say it some ZWO accessories look to be re-badged SVbony items…

Thanks for the tip, all new content I wonder?

Nah, I’m in the S, V, bony camp.

This is 35 x 3 mins with the RASA8/QHY268c/NBZ. I tried to generate a Hubble Palette type image with a synthesised blue channel, but lost some of the detail in the process, so I'm sticking with this one. Thanks for looking.

Is the KAF8300 CCD considered a “quality” mono sensor? There are a few of them up for sale now compared to 12 or 18 months ago. If I was starting out now and on a tight budget , I would get one of these, a massive step up from an uncooled DSLR, even if it is old tech.

Using weather data from an on-line source is an interesting idea, but I also wonder how reliable it would be if it is not gathering data very local to the observatory site? For example, two nights ago 70% of the sky was clear on my all sky camera, but rain was lashing down and the rain sensor closed the shutter on the dome.

Superb image, it has an intriguing 3D quality about it.

Very impressive.👍