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There's very little tolerance with the f2 RASA. I've made my own spacer/filter holder to give me the 25mm back focus. The filter at present is not sitting quite square on and causing a few distortions (left to right in above image) though that may also be due to the IDAS NB-1 filter not being well corrected for the f2 light cone. Correcting the mount PA last night has made a big difference and something I will check more often especially after working round the mount / tri-pier.

Great image and the mono reproduction does it great service - well done.

Longer session last night. Spent some time checking and adjusting the mount's PA. Then to hours total integration time on M78 and it's surrounding area. 20 subs: 10 x 240s and 10x 480s. Details: iOptron CEM60 standard mount on tri-pier RASA f2 OTA ASI294 MC Pro OSC camera with Idas NB-1 filter SG Pro as capture software, Processing mixed APP & PI

Really wanted to make a session of this image tonight but clouds cut it down to 3 subs: 2x 240s 1x 480s. Will try again tomorrow....

Hi Sean, @Craney I have a tri-pier for my CEM60. There are a number of register holes in the black column giving positive positions. You can then alter the leg angles to give alternate heights. Great mount Brian - good luck with the sale. The wiring mods look good, thought about that on mine but a job for 'later'.

NOW SOLD

Photos. These show: All the items, OTA, Corrector, Bob's knobs, adapters, 2 / 1.25 inch diagonal, Losmandy dovetail, diagonal mounted. The diagonal has both visual back and 2 inch slip in connectors + 1.25 inch step down.

SOLD - Sale completed Hi Selling my Celestron Edge HD 8, Bob's knobs, 2 inch and 1.25 inch T adapters, 2 inch prism, finder, additional Losmandy dovetail bar, corrector cover and original box £800 collection from Hereford area. Photos to follow.

You need to align the focuser with the secondary optic first, then you can align the optics. If the focuser isn't aligned orthogonal to the OA then your plane of focus will never match the plane of the sensor.

Well done Peter - great imaging.

SOLD I'm selling my Myford ML10 screwcutting lathe as I'm needing something with a greater capacity. Just about to strip it down for an annual clean and service so I'll get some photos shot during the process. Looking for circa £650

Thanks @johninderby - no hadn't seen that just a blank screen...

Anyone else using Photobucket - haven't been able to log in for a couple of days. Tried different browsers no luck that way either...

Like it very much

@576 It has a 404 error which usually means its sold.

@Skyline Yes shot with the ASI 294. Earlier problems I had with amp glow have gone since using flat darks, flats and dark frames for calibration and dropping bias frames. Also I now do early processing using APP then move to either PI or PS. I can't get the hang of colour in APP (yet). @carole & @JamesF Thanks for the comments

Thoroughly enjoyed this imaging session gathering the light frames. Now came the task of gathering the calibration subs. I pulled together: darks, flats and flat/darks, no bias frames. These were all put through APP and some 3 hrs later out came a joined up mosaic. I used APP to remove light pollution and calibrate the background. Further processing has been done in PS-CS3. This mainly entailed saturation with Hue/saturation selecting different colours and either increasing or decreasing their levels. I'm sure I could keep playing with the image and make use of masks to control M42's core more. What I will probably do though is take a set of shorter exposures and blend them in. Probably the final on this one. Hope you like.

Just a mad thought but you have set the commander software to 'sidereal' not lunar or solar rates? Just seems that whatever your doing regardless of exposure the results look similar - hence the wrong guide rate thought...

Out with the CEM25P again last night. I mounted the William Optics ZS73 again + a Baader 7nm H-alpha filter and the mono Nikon d5100. NGC1499 (California nebula) was one of the targets. This image is 15x 300s subs, processed in APP and PS-CS3.

This is a partial process - only the 60 second subs from each panel have been merged to see if the whole thing worked. Shot last night it comprises four horizontal panels, stacked vertically then rotated for posting. Each panel has 3x 60s subs, processed in APP and PS-CS3. Details: Scope: RASA 8 Mount CEM60 Standard on tri-pier Camera: ASI294MC Pro (gain 122 - offset 30) Guiding: PHD2 via TS 80mm guide scope and asi120MM-S camera. Capture: SG-Pro Now to process the other subs... Hope you like All subs: Each panel has: 4x 30 s, 4x 60s, 5x180s and 5x 240s. Processing as above, no calibration frames taken for this image yet. This is a lights only mosaic.

With my iEQ45 Pro when telling it to go to zero I loosened both clutches, let the mount do it's thing then set the clutches with weights down scope pointing north...

I don't have an EC version of the CEM60 but have a similar set-up. You've run a PA drift align and got fairly flat traces for both axii so that should be fine. The CEM's are dead easy to balance so I presume you've balanced first the dec then RA axles - ruling out balance problems The encoders are just providing a constant drive rate (PPEC) they're not sensing against the stars so your guide pulses should be OK. However your problems do look RA oriented. I have a Williams 73 ZS with finder guider, my calibration steps are much higher circa 2500 and calibration steps are usually 14/15 west, 6 east and 8/10 for north/south steps. At 500 it would take probably 30-40 steps to reach the +25 threshold. Is the focal length of your guider set correctly? Hysterysis I set to 30, guiding 1 rarely use anything other than 2 seconds, minimum mo 0.15 (dec & RA) aggression 70% RA 30% dec. To me your Calibration steps are too short (Brain / Guiding tab) and your minmo set to zero doesn't allow the mount to settle and it's always chasing itself. Cables: are they dragging or fouling anything...

@Danjc Great thread. I have the same PPB and it works a treat. I run 2 dew bands, camera, mount and focuser. While my USB's plug into the back of my CEM60. Like you I ended up getting Lindy USB cables to make sure the USB's didn't cause issues. I find the 4 power out puts, 2 dew bands and the environmental indicator do all I need. Thanks.

I've only really used this mount once seriously but I have to say I've been surprised: it's smooth, it's quiet, it tracks well unguided (though only taken to 60s so far), guides well too (5 min subs). Guiding here used a 9x50mm finder and asi120MM-S camera. I chose a couple of well know targets and shot them using a William Optics ZS 73 + (1x) flat73a + Nikon D5100 mounted on the CEM25P. Each image is built from 5x 300s subs, processed in PI. Capture via APT. No filters used. I purchased the mount and light weight tripod from FLO and set the tripod, mount and OTA assembly on our patio area. Comprising stone slabs. I have a motor cycle 12 VDC power source which I've hung from the equipment tray. USB cables from the guide camera, 2 leads from the Nikon and the mount all fed into a non powered USB hub at the mount with a single USB extension cable back to the laptop in the conservatory. iOptron's Commander software was installed, APT used for captures, Bahtinov mask (built into the ZS 73 hood) used for manual focusing all images saved to camera card (card slot on my old laptop U/S). Images imported into PI for alignment, stacking and levels adjustment, resizing and saved as jpg files. My D5100 is a mono modified DSLR so some cropping has been done to remove the ragged edges around the chip/sensor. See uncropped single sub. Setting up. I started by assembling the head onto the tripod minus scope and counterweight but including the motor cycle battery. Getting the head polar aligned using a phone app to indicate the position of Polaris. I then added the OTA and counterweight and rechecked the PA via the polar scope (minor adjustment required) I find this unloaded/loaded approach to PA easier than making bigger adjustments with a loaded tripod. Connected the four USB leads to a hub located on the equipment tray/leg spreader at the mount and USB extension to a Win 7 laptop. Fired up Commander, PHD2 and APT. APT's plate solve used to centre objects and sync when centred. As this was a first real outing with the CEM25P I did a two star alignment/sync to on a couple of widely spaced stars before heading foe Andromeda and M45. I set-up a plan in APT to take 5x 300s subs. These were processed in PI only. Will follow this up later when weather permits.

Pixel scale 2.39 sec/p