drjolo

The first things that come to my mind are: are the clutches engaged properly? is mount polar aligned? If not, then the target may slowly drift out of the field of view is sidereal tracking enabled? If for example, lunar tracking is on, then the target will drift away AVX once properly set up should keep the target for a long time.

At the very end of astronomical winter clouds eventually went away for a few nights. I still have a 3 by 2 degrees FOV setup in my backyard shed, so I have pointed it to the Virgo cluster and captured six hours of luminance to check it out. Despite the light polluted sky (19-19.5 mag/arcsec2) some interesting details and views appeared in the frame. Imaged with TecnoSky 90/540 Owl refractor and QHY268M camera on EQ6 mount. Baader L filter, 175x2 minutes. Full frame view: NGC4438 area NGC4440 with a faint dwarf galaxy or galaxy cluster above it http://simbad.cds.unistra.fr/simbad/sim-id?Ident=%401934832&Name=LEDA 40932&submit=submit - there are more such faint blobs around the frame. NGC4459 lenticular galaxy, and another faint blob above the image center and a bit left And also the M87 jet ( at 2 o'clock )- less stretched, but scaled up 200%. Ten years ago I would never hope to catch some decent galaxy images with a 90mm refractor

I do not try reprocessing attempts often, but a week ago or so I took a look at the Cocoon image I made last autumn and I had an idea of how to, hm, "upgrade" it. I wanted it to be more dusty and fluffy to reveal some background structures. The area is full of stars that obscure it, so I extracted them and shrank them a few times. Then I stretched the background a bit and merged it back. And the outcome is below. Despite the fact, the data was captured in my background under Bortle 6 sky the amount of dust revealed is quite significant. Subframes were captured with TecnoSky 90/540 Owl refractor and QHY268M camera with LRGB filters. It is about 12 hours of total integration time. Thanks for watching!

Rupes Recta, Ptolemaeus, Alphonsus, and Arzachel imaged yesterday. SCT8, PlayerOne Saturn-C, IR cut and barlow - about 3200mm FL. 10% of 3000 frames stacked.

Archimedes and Montes Apenninus captured yesterday. SCT8, PlayerOne Saturn-C, IR cut and barlow - about 3200mm FL. 10% of 2000 frames stacked.

It is a really hard call for me. There are a few places where some small stars or star remnants were left by StarNet2 and were removed completely by StarX. On the other hand in a few places, the nebulosity detail seems to be a bit better preserved by StarNet2, but the differences are really super small. One thing I forgot to mention is that StarNet2 is much faster than StarX, about 5-6 times faster. It is not a big issue for a single image processing, but a few days ago I decided to process with StarXTerminator 200 comet images to remove stars before stacking. It took almost 30 hours. It is easy to calculate how much time we can save using StarNet2 for that task. The PC is an i7 with 16GB RAM, subframes were 24Mpx large. There are still two weeks of StarX trial left, so maybe I will make up my mind somehow

I am currently considering a StarXTerminator purchase and decided to make a small comparison on some frames I captured last year. And here are the results. Each comparison contains six images. The first row is the wider view, and the second row is a 1:1 crop of detail. Starting from the left there is a raw stack, then StarXTerminator outcome and StarNet2 outcome. Both tools were installed as plugins to PixInsight and worked at default settings. M31 fragment imaged with WO ED80 scope and QHY247C color camera: Rosette nebula in Ha band imaged with 90mm APO and QHY268M camera: Alnitak area in Ha band imaged with 90mm APO and QHY268M camera: Tadpoles imaged with 90mm APO and QHY268M camera with Baader RGB filters: All the samples above were processed in the linear phase before any stretching was applied. The last one is after stretching. Lion nebula fragment with 90mm APO and QHY268M camera through Baader HSO filters: And just for fun Cocoon nebula with some stars removed (StarNet2 was used here). Quite a dramatic view

Does anyone use Askar FMA230 scope? According to the manual, the backfocus distance is 55mm, and I also confirmed with the manufacturer the distance is measured from point 2 (thread start), not 1. but I achieved the best results with a full-frame camera at 52-53mm distance, so the focuser ring at 16.5 point. Can you share your backfocus distances? At 55mm APSC frame was okay, but full-frame corners were significantly distorted. Here is how FF corners look like at 52mm (no calibration frames, so vignetting visible): And the first light - 10x30s stack (not calibrated) of comet next to Aldebaran: Sony A7II, SW Adventurer.

At last, I was able to capture this fast runner. It travels the apparent diameter of the Moon within 3 hours! The image below is about 1.5 hours of LRGB subframes captured with a QHY268M camera and 90/540 TecnoSky Owl refractor under the suburban sky (around 19.0 mag/arcsec2). Nothing spectacular was around the comet, so just some regular stars in Auriga in the background. Just a souvenir image of the comet - first clear nights this year in my location.

My current setup field of view (3x2 degrees) allows at last to capture Rosette in a nice frame, so I started the HSO project. During the last two nights (the first clear nights this year at my location) I captured 5 hours of frames with a hydrogen alpha filter and here is the result. Snow and an almost full Moon made extra light pollution, but the target is quite bright and a lot of photons were captured Full frame (maybe stretched a bit too much) and enlarged center. TecnoSky 90/540 Owl, 0.8x FF/FR, QHY268M, Baader filters, 110x3 minutes, Bortle 6 sky, Moon, transparency good.

Just an idea - maybe try to do factory reset of the HC. It does not seem to be mechanical issue, at least basing on your description. If you can rotate the Dec stepper shaft with your fingers (when power is off) then the worm gear is most probably fine.

It is not uncommon for that mount type, that worm wheel is not perfectly symmetric, and in some position the play will be significant, while at other it will be not. The best you can do is to cancel the play in the "tightest" worm wheel position, because if you cancel it at the opposite, then there will be an excessive friction in the "tight" position. One way or another the backlash is not a big issue, unless it is really big.

Is there a separate cable that connects mount head to Dec motor part? If so, you may just to test the cable using multimeter if all wires are ok. Preparing that cable may be pretty easy.

You may connect some equipment via USB hub. I think you may start trying with just a simple passive USB2.0 hub and connect mount and EAF via hub, because these two setup components require low bandwith and no active power (unless EAF is powered via USB, so then you need an active USB hub).

Elegant solution for all the fat cables and voltage drops. A TVS diode would be also a solution.

Hm, as far as I know from other solutions (not iOptron, however) microstepping resolution is controlled dynamically from the code and control lines from CPU, so with GoTo the resolution is lower to achieve larger speed. If that is the case for iOptron as well, that would require firmware changes I think.

Yes, I know it is not a backlash literally, but looks like. And PHD2 was even able to train how to remove this "backlash" in Dec. I thought about replacing the motor, because it is regular NEMA17 size, unfortunately there is no room to put there longer stepper version in CEM26. It was my third mount model from iOptron and I am cured now of iOptron mounts (and Bresser as well - but that is different story).

Unfortunately spring loaded gears can have backlash depending on the stepper torque and the actual pressure made by the spring. When I did adjustment in CEM26 according to the manual (so fully tighten and then loose by 1/2 or 3/4 turn) I got backlash. I have put a printed 12 cm lever on the Dec motor shaft like this: to monitor small movements. I have been sending pulses manually with HC at 1x speed. And the tests are as follows: - when the Dec clutch is disengaged the motor reacts immediately for the pulses when the direction changes, there is no backlash - when the Dec clutch is engaged, there is a backlash in the Dec motor axis, and after changing guide pulses direction the motor starts to move in the opposite direction after some time (500-3000ms) This backlash is caused by the increased torque required to move Dec worm when the clutch is engaged. Microstepping torque depends on microstepping resolution and for 1/128 it is like 1% of the full step torque, and for 1/32 step it is like 4% of the full step torque. This is apparently not enough to rotate the axis during small guide corrections, and this microstepping torque needs to accumulate for some time to be able to move the worm. I have loosened clutch tension a little (1/4 and then 1/2 allen key turn), and the backlash seems to be lower but did not disappear. Once the spring load was very light and balancing was perfect, then backlash was minimal.

If such a small difference causes RA to wobble, then maybe it is as newbie alert wrote - some movement in the worm cradle, or play along the RA worm axis. These are scenarios 2 and 3 from the screen below (comes from CEM26 adjustment guide)

I also found out that SY135 is sensitive to backfocus - if you have sharp stars and the focus ring is not at the infinity mark, they may be distorted in the corners. The larger sensor the more precise backfocus distance should be.

These spring loaded CEM40, CEM26 and similar mounts are very susceptible to perfect balancing - in RA, Dec, but also along the telescope axis. So if you have heavy focuser motor or guide scope on the side, it needs to be balanced on the opposite side of the OTA. Worm gear tension needs to be adjusted as light as possible to cancel the play, but no more. Stepper motors in these mounts are undersized and such behavior may be a reason of accumulation of microsteps that are released after some time.

SSD and USB3.0 will be good, and I suggest to avoid entry level CPU like Celeron or Atom. I have mini PC with N3350 processor and with running SGPro and PHD2 with multi star guiding it already reaches 100% CPU during the most of the time. Any i3 or i5 family CPU will be much better.

Impressive detail and elegant color! Which reducer do you use? Optec?

Four years later I picked Abell 1185 cluster to process it one more time - data as before 120x1 minute of luminance with Meade ACF 10" telescope and QHY163M camera.

Two years later I have attempted to process M63 data one more time - data as before 375x2 minutes with Meade ACF 10" telescope and Baader LRGB filters with QHY163M camera.