Leo Triplet with M3 side order

[Uranium235]

I get the same star shapes with my 150P and slanted in the same direction. I thought it was flexure in the finder guider but I haven't got to the bottom of it yet.

I don't get reflections from the MPCC with the DSLR but I do get nasty big diffraction patterns from the primary mirror clips. Have you had to do anything to avoid that? I was thinking of either flocking the ends of the clips, adding a circular mask to cover them or maybe even a silicone glue mod on the clips.

I hadnt thought of the mirror clips as ever being a problem, actually... I think mine are black. I will have a look later on and see whats going on down there. If yours are silver, you might just get away with a black marker - just be careful not to slip.... oops!

Ive collimated it a few times now, making sure the spider vanes are all the same length, getting the secondary in the (apparently) right place, then using a sight tube and cheshire to finish it off. Still the same result. It cant be flex from the finderguider because that bracket is as solid as they come, and it performed well enough on the ED80 for the triplet.

If it still does it after I get the NEQ6 (so I can rule out flex/tracking), then its a case of more messing about - or getting a 2nd ED80 for a double barrelled shotgun affair

[Chris]

Thats almost right. last time I took it out, I weighed the entire setup on electronic scales and it weighed 7.4kg (right at the "safe" limit for guiding on the CG5-GT). Thats with the 150P, tube rings & dovetail, finderguider & bracket, plus the imaging train (MPCC, FW, 314L+).

A 150P and the EQ5 would be a much better match. But id be temped to get rid of the mount and keep the 200P

Yeah the 200p is 9kg just for the OTA, rings, and dovetail so it would be way over for imaging unless you use a finder guider and have no wind. I think that if he's plannig an obsy/shed type thing he should keep the 200p and get an HEQ5 or 6, but if he needs something he can lug around he should get a lighter OTA and maybe just upgrade the EQ5 to Pro with the Kit? I Bought my mk1 HEQ5 with an old blue tube 200p and I tried for a while with it carrying it out of the house in two parts the mount and the OTA and it was hernia inducing especially when it came to trying to mount the OTA with its undersized dovetail, so I sold the OTA. I'm considering a 200p again now that I'm building an Obsy where one can live:)

The slanted star shapes you guys are getting with your 150p's is very curious, the fact that both of you are getting exactly the same artifacts suggests that its the 150p rather than the rest of the setup causing it, unless you guys had the same setup which I don't think you have, although if it was flexure causing your imaging train not to be orthoganal would you get elongated stars uniformely across the field as above, my zs66 suffers focuser sag and I get elengated stars just in one corner as a result.

[RikM]

My clips are black but I still get big 'iron cross' style patterns around bright stars. It goes away if I image on both sides of the meridian.

I have my lot on an NEQ6 and I still get the same star shapes, so if you do figure out what it is, please share. I will make sure to do likewise

[Uranium235]

My clips are black but I still get big 'iron cross' style patterns around bright stars. It goes away if I image on both sides of the meridian.

I have my lot on an NEQ6 and I still get the same star shapes, so if you do figure out what it is, please share. I will make sure to do likewise

Ahhh... the "iron cross", I think know what youre talking about now. Ive seen that before, but isnt that just the norm with newts doing long exposures on bright stars? Classic example would be M45.

If (by some miracle) we get another chance for clear sky I will try another test, re-configure the imaging train, and guide on a spot where I know its trouble-free(ish) from backlash.

Have you ever cleaned your primary? If you havent, maybe I can rule that out as a cause. Ive already ruled out tube currents because when those test subs were taken, the OTA had already been outside for 5 hours. Didnt seem to suffer so much on M3 though, so im a bit confused there.

I will have a mess with the raw data again since I remember doing a bit of star rounding during processing. If I find a cure, I will be sure to let you know

[RikM]

Never cleaned the primary, no. I still get the funny stars sometimes even with a flat guide trace.

I don't get the same cross pattern from the 250PX and that has 6x mirror clips so I am pretty sure it's the clips. Nothing a ring mask won't fix

[Uranium235]

Ring mask ey? Hmmm... sounds interesting, I might have a go at making one too. If it works, cool. If it doesnt, its easily removed. Please post a pic if you make one, just so I can see what I should be aiming for.

[Shibby]

Have you checked the tilt of the secondary Rob? I had to adjust mine slighlty, this could explain slightly oval stars. But then any kind of guiding error would do also.

My stars tend to be round, but with a bite taken out of them due to the focuser tube protrusion.

[Uranium235]

Have you checked the tilt of the secondary Rob? I had to adjust mine slighlty, this could explain slightly oval stars. But then any kind of guiding error would do also.

My stars tend to be round, but with a bite taken out of them due to the focuser tube protrusion.

Thanks Lewis, I will check it again tonight (looking cloudy again). My stars are the exact opposite, round in 3 quarters with a bulge in the last quater. Its something that also appears to crop up when focusing too (no guiding needed as 0.5s loop).

Its just a pain in the bot when adjusting the secondary tilt (using the centre screw) as I have to try and get two hands on it while looking through the sight tube at the same time (otherwise it rotates when i tighten up the screw)... a bit fiddly!

[Coco]

Very nice indeed, love those three galaxies and you nailed em as they look there best