pharscape

A maybe related issue: I had intermittent/poor USB connection on the CEM70G USB hub. While I was identifying my DEC guiding issues I dissembled the DEC plate and noticed that the connector to the hub is just a push fit board edge connector. The wiring loom in the DEC plate is held in place by foam compression pad - not much is stopping the hub cable from being dragged out of its socket as the plate rotates or if you previously removed the main controller board and maybe pulled the cable down a bit😉. I re-seated the connector and my USB issues have stopped. The iguider (which I don't use) is powered from the hub board and it too is now detected reliably. At least on my CEM70G the wiring to the DEC plate is part of a bundle that go off to the ipolar....

Here is the belt tensioner:

I've had images like that when the guiding SW tries to correct a shift due to something loose or dragging cables. Are all your images like that regardless of exposure time or where you point the scope? If it only seems to happen with long exposures, I'd suspect a flexure/tracking/guiding issue. If you are concerned it's a collimation issue then try rotating the main scope and camera in the rings. If the aberration rotates as well the problem is likely a collimation issue somewhere between the primary lens and the camera sensor (something not square on to the optical path.).

The cheapest ebay/amazon brass inserts have no pull strength so I chose the slightly more expensive cross gnurled version. When placed well they have good strength, trouble is the brass/plastic keeps the heat and they move about easily before the plastic sets. I was thinking about making a jig but nuts will max the pull strength and is a lot simpler. Just not relishing the 15hr print 😬 so I won't make that change until I see a need for another design tweak. The buck converter is a generic design, XL4015 based, with two trim pots. Ordered from Az-delivery. They advertised the unit only having the voltage trimmer but these seemed to be a revised design which not all their docs have been updated for. The second trim pot is the current limiter which I have set to max. I found the reason for the variable focus/ auto focus failure - my false economy. I didn't zero the stepper before rotating the lens and the timing belt came off the short piece of timing-belt I used for the ring teeth. The simple solution is to just fit a band of timing belt around the whole focus ring. Judging by my first night experience, my enclosed design keeps the Samyang warm and dew free whereas the guide-scope was suffering (I hadn't intended a long session so didn't bother to fit the dew strap to the guider). And proof of the pudding is in the eating: 56 mins Ha and 30 mins Oiii. There is some star distortion in the top right quadrant and Sadr is not round - tilt I think so I've ordered the Samyang M48 adapter from FLO.

Thanks, its my first attempt at using Fusion 360, it's not pretty but it is robust 😄. I just need to work out why auto-focus only worked once (I suspect belt tension/backlash) then I can begin full Ekos automation. I will be changing the design a little to use captive nuts. Heat-staking the knurled inserts is very unsatisfactory, it is too easy to go wrong, variable in its bonding and alignment

Well it's working pretty much as planned. Managed an hour or so of the Sadr region as a bonus. Manual focus with ekos and bhatinov was easy. Automated focus worked once, I think backlash was increasing. Lum, Ha and Oiii seem to have very different focal points, I guess that is an F2 lens effect. I have a few issues to resolve around rotating the lens. I'll probably fit timing belt all the way round the ring. Most of my problems are with learning ekos and trying to read the fine text at night. I need to attack the gnome configuration. It isn't out of the box ready for small screens and night time old eyes IMO.

Yet another 135mm mounting solution. This one is enclosed with main electronics attached in a side box. Most other solutions are open plan with separate front and rear rings. My idea is to make something that is self-contained, hopefully doesn't suffer flexure, robust enough to travel as one unit and keeping wiring in place and condensation off the lens and electronics. The base is fitted with a NEMA17 stepper + 16 tooth wheel to drive the Samyang focuser via a clamped on larger diameter (98mm) ring. It provides about 11:1 reduction - full focus range is about 1100 steps. A belt tensioner (not shown) is attached to the stepper motor and is adjustable via access holes at the front of the base. Daylight testing gives me infinity focus at around step 37 (0 is the infinity stop of the lens), with defocus obvious at +- 3 steps so not a lot of margin for fine tuning. The forecast clear skies tonight should allow first light to check if the step resolution is good enough for a bhatinov mask focus test. The side enclosure contains an RPI4 running Astroberry , Waveshare stepper controller and 12V to 5V @5A buck converter. The Rpi boots from the SSD velcroed on the side (it's also the removable media for the images). The enclosure slots into the side of the base with only wires connecting to the stepper. To provide grip I superglued a section of timing belt to the ring. Since the 135mm focuser's full rotation is 180 degrees this is adequate. The lens is sandwiched with some 2mm crafting foam to pack the rings. Once the concept is proven I may refine the styling. Currently its printed in four parts: Bottom, top, side panel, focuser ring and belt tensioner.

That is Flashforge Red : https://www.amazon.co.uk/gp/slredirect/picassoRedirect.html/ref=pa_sp_atf_aps_sr_pg1_1?ie=UTF8&adId=A03080183D5VZD3JJPIFM&url=%2FFLASHFORGE%C2%AE-Printing-Filament-1-75mm-Creator-Red%2Fdp%2FB072LNZXBD%2Fref%3Dsr_1_1_sspa%3Fcrid%3D3T2WV2LD6EP34%26keywords%3Dflashforge%2Bred%2Bpla%26qid%3D1654082872%26sprefix%3Dflashforge%2Bred%2Bpla%2Caps%2C59%26sr%3D8-1-spons%26psc%3D1&qualifier=1654082872&id=8210578642908044&widgetName=sp_atf

This is an accessory for the ASi1600 and similarly sized ZWO cameras (78mm diam). It provides strong anchor points for cable tidies, strain relief for the front plate dew heater and a rotation pointer for accurate framing over multiple sessions. https://www.thingiverse.com/thing:5364095 I chose a 2.6mm base for strength which meant the stock M3 screws had to be swapped for M3x10mm. Hopefully you will find it useful. Cheers, Paul

I think it depends on your equipment and use case. I don't have experience of Li-ion batteries but my web search suggested they are not a good match for equipment that needs a voltage above 12V for a long periods. (Unless you run them with an external regulator to keep the output above 12V. ) An unregulated fully charged 12V Li-ion battery is I believe 3 cells of 4.2V so 12.6V max (nominal voltage is 3.7 so 11.1V on average). Using discharge curves found on the web the battery voltage will continue falling during discharge dropping as low as 9V in the end. If your setup can handle that then great. Most of the credible reviews I have read for Li-ion power tanks (that measure these things) report the 12V outputs are unregulated just like this. Conversely my tests show LiFePo4 12V batteries have a fully charged initial output voltage 13.4+V and voltage falls slowly under load staying above 12V even when it is almost exhausted (less than 10% capacity). (A new Lead Acid battery fully charged can also be up to 13.7V and most circuits are designed for battery use.) My HEQ5 likes a voltage over 12V for reliable operation. Cheers, Paul

Thanks. The reason I've shied away from using Lum is my (perhaps unfounded) unease that for example a strong red structure picked up in Lum is used to emphasise R, G and B when it should only impact R. You don't really have that issue/choice in NB as Ha and the others are often very different and L may not see enough data without stars blowing out.

With my setup I find 30sec subs seem to always work with low chance of burnt out stars.

I'm also interested in this answer. I have not been capturing any Lum and bright details with goods SNR look fine but the fainter stuff looks a bit rougher than I've seen in other's images. I suspect I'm missing a trick.

If its just stars that need RGB I've gone as short as 15mins per colour but I normally do 30mins per just so the spikes can be clean on bright stars. If you are going to have spikes, make them nice ones. Most of my imaging is a F4.8. I've not looked at the minimum I can get away with.

Hi all, I haven't posted an image to this forum for several years but I now have more free-time to image regularly - there is an upside to working from home This is NGC 4725 and cohorts. It looks NGC 4725 had a tangle with 4747 and neither came off well. Imaged from the 22nd to 25th March, total integration time was 9 hours and 15 minutes, (2h20 Blue, 2hr53 G, 2hr05 Red, 1h56 Ha). Imaged with an ASI1600mm pro and ZWO filters with an ancient Orion Optics UK 250mm Newt on a CEM70G. Captured with N.I.N.A, processed in PI and tweaked in Paint Shop pro. That was a remarkable few days of good weather.

I've been using a Baudens 240Wh (22Ah) tank. Its a LiFePo4 battery pack. That runs an HEQ5, ASIAIR pro, ASI1600mm pro, 2x dew straps, ASI120mm guidescope. With dew straps on max it runs for 5+hrs. If you add the cost of a plastic box to keep moisture off (which I use to store all the cables in anyway) its a bargain at twice the capacity of the smaller astro-units and when I bought it is was also cheaper. To run all night (8hrs+) I have another 240Wh tank that I built myself for under £130. (£114 for the LifePo4 battery + charger and the rest of the cost was for switches and a small display:

Learn by my mistake and be cautious and get yourself a cheap multi-meter at the same time - just to check the output voltage is what you want... My experience of a similar device: "Raeisusp 12V-24V step-down ACK-E8" was that the voltage was too high for my 550D (and probably the other cameras it claimed compatible) , and even worse the voltage-out varied by the voltage-in! Luckily my camera wasn't damaged after it shutdown (thank you Canon). I checked the module's label to find the output was proportional to the input : It stated 12v/24v 8.4V/8.7V! So running at 13.4V pushed the supplied voltage too high for the camera to handle. I opened up the module and replaced the circuit with an adjustable one set to 8.1V and all has been good since.