CraigT82

I often find myself on Klaus' website drooling over the CF tubes! How do you find the performance of the tube over the standard SW one? I have got a vague 5 year plan for a self build newt which involves a 12" Nichol mirror in and Aurora cell all wrapped up in one of Klaus' carbon honeycomb tubes with matching carbon rings.

If you ask me that's a fabulous image! A lot of the work I see online is well overcooked (not so much on here but on other social media platforms) with contrast and saturation boosted to the max and a ton of sharpening and noise reduction thrown on top, which makes them look reasonably impressive at first glance in a preview, but not so nice when viewed at full size. Your posted image is the opposite of that in my opinion, conservatively processed, balanced and sympathetic to the data. A joy to look at. I think that a little more time on this particular image with the curves tool and you could get the look you're after without sacrificing the data?

Ive seen a few people reinforcing the upper tubes with sheet aluminium riveted/screwed on the inside or outside of the OTA, to make it all stiffer up at that end. I wonder if you could 3D print a section of tube, with an OD just less than the ID of your OTA and a wall thickness of a couple of mill, to slide down inside the OTA beneath the focuser and reinforce that area? Could even glue it in place instead of screws or rivets so it would be an invisible reinforcement?

Yeah I think that's the crux of it really, is there any point chasing those small gains from ADCs/winjupos when the seeing is by far the limiting factor where we are? For me it's a yes as there will be the occasional night when the seeing is perfect and I will want everything else to be perfect too so afterwards I have no regrets about what I might have captured if only I used this or did that. Saying that though I find that derotation only works well when seeing was good and there are enough clear details visible to align the images properly, if the input images aren't great then the alignment is just guesswork and will probably just make things worse.

Yes Venus does require some different techniques. It can show detail when imaged in the NIR but I've only seen that from observatory class scopes and I've certainly never managed to get any details in the NIR (685nm and 850nm longpass I've tried). This detail comes from the lower altitude clouds. Using a UV filter you can get nice upper altitude cloud details when conditions are good. If the mood strikes you can average the IR and UV captures to create a green channel, and then combine the three with IR as red and UV as blue. Here is an example from last year with a 220mm scope.

I know what you mean with the thermals, the only view south for me is straight down the street in front of my house... which comprises lovely new black asphalt! shooting over that after a warm day is asking for trouble but I've got no choice unless I go mobile (not likely with a 12" newt). Looking at your clip I think you might benefit from an ADC, there is a distinct blue fringe at the top and red at the bottom.

SDSO have tweeted a statement and a Paypal link for anyone wishing to donate... https://www.paypal.com/donate/?hosted_button_id=SCS9A6JME2S6W#

Excellent Neil, conditions are getting better by the day.

Just looking at the cheaper EQ2 'economy' drive (without the multi speed handset) and I think it would fit your mount. It seems to go on the other side of the worm shaft, have a look at this thread where someone put one on a Polaris...

Ah I didn't even look at the price of it! I think it's more expensive because it comes with the multi speed handset which is very handy to have, whereas the cheaper one is basically on or off. There is a slightly cheaper one on ebay right now... https://www.ebay.co.uk/itm/Skywatcher-RA-Motor-Drive-With-Multi-Speed-Handset-For-EQ2-Mount-/333857919598?_trksid=p2349624.m46890.l49286

Hmmm... if your Polaris mount is like the one in the right hand side of the pic below I'm fairly certain you can use an EQ-2 RA drive, but maybe the older style one... https://www.rothervalleyoptics.co.uk/skywatcher-ra-motor-drive-for-eq2-with-multi-speed-handset.html Here is a few pics I've grabbed off the et to show how the Polaris mount is the same as the EQ-2 and how the drive should fit on there. If your mount is different than the one pictured then if you post a pic of it we can investigate more.

You could try polishing the brass of the drum all around, just enough so what when you refit it and rotate it again, any binding spots will rough up the polished finish so you can remove it again and see where it is binding. The binding isn't a major issue though as in use and tracking the clutches are locked and so there is no movement between housing and brass drum. If you can get it to freely rotate it might make balancing the OTA easier though.

Thanks Mark. How are you getting on with the old f/4? I saw you were having some chip alignment issues with the cam? That is a bit of an experimental feature at the minute, it is to be used with the ADC. When the ADC is adjusted the target moves, quite often right off the camera sensor which then requires you to move the scope to get it back on. The X-Y adjuster allows me to move the camera itself rather than the scope to get the target back. The theory being that the target remains exactly on-axis and in the sharpest part of the FoV. Not used it in anger yet so don't know if it works! It is also very handy for making very fine collimation adjustments whilst looking through the cheshire, which are often needed once I've plugged the imaging train into the focuser (having colimated the scope first without the imaging train) as the extra weight and length of the train causes the collimation to shift very slightly (due to the tube flexing I think).

Looking at pics I'm reasonably sure the 130 polaris mount is the same as the skywatcher EQ-2, in which case you can buy one of these... https://www.firstlightoptics.com/sky-watcher-mount-accessories/ra-single-speed-motor-drive-for-eq-2.html Best to email them to check it is compatible though.

Haha yes it does! Got some Nasa worm logo stickers on order and tempted to add some fake solar panels but they won't do much but catch the wind!

Eventually got round to fitting the lakeside motor to the steeltrack. Had a but of an issue withthe bracket not fitting the focuser at all (despite being sold as a steeltrack specific bracket) but got there in the end. Also finished wrapping the tube to help keep tube currents at bay. Bit of a mess but doesn't need to look pretty.

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I've only posted a scope twice but each time I let the buyer know that there will be no insurance for breakages, and tell them if they want me to post it they can take the responsibility. I will pack it up as well as I can, In it's original packaging if poss, and if it arrives broken then that's that. If the buyer won't accept that then no sale. Used parcel force 48 each time, no probs.

4 screws like this...? https://www.astrosystems.biz/sechold.htm

And FLO

Yes it's perfectly possible. Did the exact same thing with my 200p dob ota. You just need the 235mm tube rings and a dovetail bar. I'd recommend a losmandy dovetail as it's a hefty scope, though you may need to upgrade the saddle on the skytee to take a losmandy dovetail.

You just need a UV/IR cut filter for taking colour images. You can also use an IR pass filter for steadying the seeing and capturing a sharper luminance channel to add to a colour image (this works very well on Saturn in particular). The QHY version of the 462 comes with these filters in the box, not sure if the ZWO version does.

Are you wanting colour or mono camera? Your f/8 scope with a 2x barlow will be a decent match for one of the 2.9um pixel cameras, so you got the 462 (colour) or the 290 (mono) to choose from there. The 290 also comes in colour flavour too but is slightly less impressive on paper in terms of read noise than the 462. The 462 does have quite a bit of overlap between the different colours of it's bayer matrix, which isn't bad but can lead to a distinctive colour 'look', but as always colours can be tweaked after the case. It also has excellent IR performance so is a really versatile camera in my opinion. The 224c is no slouch either and is an excellent camera with slightly larger pixels (3.75um) and it can be had cheaply. To be honest any planetary camera is capable of producing top class images. On the list of 'things that will harm the quality of your images', the choice of planetary cam is pretty low down.

Steeltrack is fitted... tomorrow's job will be to fit my lakeside motor to it and then finish wrapping the tube in radiator foil - to help stop the tube metal cooling below ambient and creating temp. deltas inside the tube.

Thanks Steve, yes for an old beast it does work well. It's had a long life before me, mounted in the obsy of a gentleman who sadly couldn't do any astro anymore due to advancing age, and I bought it from him for a pittance really (as it's a bit tatty). With a bit of work it's been brought back to full working order with the addition of goto motors and motherboard plus new worm bearings, Baader #1 grease and new Teflon shims of the correct thickness. It might yet give another 10-15 years service with regular care. I did some DSO imaging with it recently with my 200p f/6 dob OTA on board and it performed well beyond my expectations, guiding it at under 0.5" RMS when seeing was good. It's struggling a bit with the 300p and all the extra C/W on board but I don't need it to guide well, just point it where I want it and then roughly track and I'll do the rest!