almcl

I moved from RA hysteresis to predictive PEC and found a small but mesurable improvement. A few sessions ago the Guiding Assistant recommended using Low pass 2 on DEC and again switching to this produced a small improvement. At present I am trying to record a repeatable PEC curve in EQMOD to transfer to the mount's own permanent PEC playback. It hasn't been as straightforward as I'd hoped, mostly due to operator error!

With luck, a small amount (10 degrees is the azimuth adjustment, if memory serves) should be more than enough to crack a thread lock.

An alternative, if the cold cloth doesn't do it, would be to slacken off the azimuth bolts completely and try and rotate the mount head while holding the shaft - might be easier with two people - just enough to get some slack and hope it can then be unscrewed normally.

You certainly can use your Canon 450d with a lens and no telescope. A 50mm lens can give nice widefield views of, say, the Milky way and anything up to about 200 mm focal length will be pretty forgiving of tracking errors and can provide good views of some of the larger Deep Sky Objects, but perhaps for the moment just concentrate on getting used to imaging with the 150 PDS? It should an exciting and rewarding experience!

Unfortunately it's both. Here's the OP's image overlaid with an equatorial grid: PHD2 Log Viewer is a handy tool, written by one of the current developers, for analysing guiding performance. If you don't have a copy there are some details here and a download page here

Coming a little late to this, but the elongated stars may not be related to the PA issue. How are you guiding, because I have seen and had a similar issue (elongated stars when PHD2 reported OK guiding). This turned out to be differential flex between guide scope and imaging scope. The problem went away when I switched to an OAG. This may not be relevant - not sure what scope/guider arrangements you have?

There are, confusingly, two PPEC s. Within PHD2 there is Predictive Periodic Error Correction, a great algorithm in my experience (or at least my guiding seems better with it). Then there's EQMOD's PEC and finally there's the Skywatcher mount's Permanent Periodic Error Correction (Page 18 of the Skywatcher manual). According to the PHD2 gurus, PHD2's PPEC can be combined with and work well with the mount's PPEC. And the thread on Cloudy Nights (referenced in post 2 above) also suggests that they can be adjusted to work together to eliminate different frequencies of the overall error. Not sure if that's made anything clearer?

For an accurate Polar Alignment the reticule should be positioned with 0 at the top. It is very unlikely, however, that the polar scope will be oriented so that this is the case in the home position. Instead, rotate the RA axis until 6 is at the bottom and 0 is at the top. This won't affect the accuracy of the polar alignment but afterwards, for accurate Gotos, move the counterweight shaft back to straight down after you have polar aligned (and the DEC axis back its position as well). If you want to orient the reticule so that 0 is up when in the home position, it is possible by removing the scope (it unscrews) and then undoing the lenses and rotating the reticule but I found this very fiddly and never did achieve a completely accurate orientation. But for an accurate polar alignment, it is not necessary.

Here's an approximation of the 'new' polar reticule. It is intended for both northern and southern hemispheres. When observing in the north, Polaris (α UMi) should be on the circle in a position determined either by the Synscan handset or one of the many polar finder apps. In the southern hemisphere where there is no convenient pole star, Octans is used for alignment.

I've used the Autorecord PEC function. Not a fan of web instructional videos, so I followed the work flow that starts on page 9 of this document http://eq-mod.sourceforge.net/docs/eqmod_vs-pec.pdf However, I recently found something better. If you have an AZ EQ6, as I believe you do Alan, and the latest version of EQMOD it is possible to get the mount to record its own permanent PEC and to have it play it back. The instructions I followed are over on cloudy nights combining eqmod with ppec and phd2 The idea is that with the mount taking out the larger errors (probably the worm period ones) PHD2 is then able to deal with the other ones. Getting a smooth PEC curve recording took some doing - clouds kept intervening - and I haven't had a chance to check it with a long guiding session under good seeing conditions yet, but initial results look hopeful.

Does anyone have an idea of the spec for the LED that illuminates the polar scope reticule on the Skywatcher mounts (mine is specifically the AZ EQ6) ? Reason for the query is that the other night when I looked through the polarscope , instead of the nicely illuminated red field with reticule, it was very dark. Today I tried turning the LED brightness up to 100% (it's normally on 30% which is been adequate till now) and although with the polar scope removed I can see the LED shining with a fairly dim red glow, it doesn't seem to change much, however one resets the LED brightness. While this isn't a major problem, it would be nice to get it back to working properly again. Any thoughts on what could have caused this sudden loss of brightness (I am assuming it's something to do with the LED) and how to restore it would be gratefully received.

Well done, once you get it configured, AstroEQ is a great bit of kit isn't it?

I agree with Vlaiv: there's a pretty decent image there with some nice detail in the dust lanes. I had a go at your second file and although DSS seems to have done something to it, this is the result I got in a very quick go with StarTools (sorry, don't have Gimp, so couldn't do it with that). To answer the question posed in the thread title, no, I don't think you're wasting your time at all. Post processing is a separate skill that takes a little time to acquire, but if you save your data, you can always come back to it in the future and have another go - I've been reworking data from 4 years ago and sometimes produce quite noticeable improvements. Keep going would be my suggestion and don't be afraid to post results and ask questions - we can all benefit from that. Anyways, see what you think?

Yes, that's right, Yes to the first bit (Dec 90) but at Dec 90 all the RA lines meet (see image below - northern hemisphere but the principle is the same) so any RA is correct if you are pointing directly at the pole:

Do you get stars in focus on the guide camera? I ask because I would expect the distance from the OAG prism to image camera sensor to be the same as the OAG prism to guide camera sensor and it looks as though this might not be the case? Other point (and it may be the angle that the photo is taken at): is the guide camera square in the OAG holder? Only it looks tilted to the left in the lower image.

Afraid I'm a PC only person, but you might find this thread useful?

Hi Chris I started with a similar rig (SW200p on a manual EQ5) about 6 years ago. Tracking motors got added about a year later and unguided Astrophotography with an astro modded DSLR started a bit after that. Guiding, using a web cam and a spare finder scope plus a GPUSB interface, was next, although the finder was replaced by an ST 80 after a while. A more sensitive (and 10X more expensive) guide camera followed. The next improvement was replacing the Skywatcher tracking motors with stepper motors and using Tom Carpenter's AstroEQ. I still use the EQ5 with this for imaging with a 200 mm lens, but now have an AZ EQ6gt and use an Off-axis guider when imaging with the 200p. I rarely do visual now as even mighty Andromeda is a nothing more than a faint grey blur from my heavily light polluted back garden, but the images that the 200P generates still fascinate . None of the purchases (apart from the AZ EQ6) were massively expensive but with hindsight I wish I had gone straight to the AstroEQ rather than the SW tracking motors, as this not only gave much better performance but also provided a goto facility which took a lot of the frustration out of finding faint deep sky targets. The journey has been great fun and I still haven't reached the full capability of the kit, hope you enjoy it too.

For those that use it, the latest upgrade of StarTools is available on the StarTools website. There are a number of significant changes and enhancements (haven't tried them all yet) and the new version will work with any valid licence, although Ivo would appreciate licence renewals from those whose licences have expired...

+1 for Adrian's comments! If the main scope is not pointing exactly at the NCP on switch on, the first goto will likely be off. If you have a finder scope it may be worth seeing how close to the pole it is pointing before switching on power to the mount. I have a diagram of how Polaris should appear in my 9 x 50 RACI (below). If you have a similar finder, it may help? If, after a successful couple of alignments, slewing to the other side of the meridian produces a large error, then cone error may be an issue, but that's probably a topic for another day?

On my EQ6 mount the same knob is held in place by an M4 8 mm countersunk machine screw. Something like this: machine screw The screw does not affect the stability of the tripod directly, in only holds the knob in place that is used to turn the clamping bolt. Provided the clamping bolt is tight the leg will remain in position even if the knob is removed.

Here are some things to try: Make sure you are using the latest version of PHD2 ( 2.6.6 dev 1) Try using the 'other' driver for the ASI120 mini (there are 2 ASCOM drivers and a ZWO native driver - can't remember at the moment which gives the better results, so swapping and seeing may be a good idea) Try switching from 16 bit to 8 bit images Post your PHD2 guide and debug logs over on the PHD guiding forum If you are connecting via a USB 3 port, switch to a USB 2 one

Autodev at the outset is intended to show up problems within the image. Crop (if necessary) followed by bin (again if required) then wipe, using which ever preset is appropriate, then a further autodev or dev and then the rest of the modules as required in the order shown in the video here: https://www.youtube.com/watch?v=IDY3ov2dQe4 Your data looks (although it's hard to tell from just the screen shots) as if you might well have some stuff there once the colour cast is removed.

Inspired by Steve's (Steppenwolf) post on Simeis 57 and the responses, I thought I'd have a go at the same general area in Ha with my 200 mm lens, while waiting for astro dark to return and the moon to go away. Tried a mosaic for the first time as well. There does seem to quite a bit going on in the area and I haven't sorted out all the different structures yet, but here's where it's got to so far (4 panel mosaic with Canon 200mm lens on Canon 700D, 12mm Ha filter, with approx 1 hour's integration for each panel): The crescent, the propeller and the cooling tower are all there, but so are quite a few other items which didn't show up on Astrometry's solve (http://nova.astrometry.net/user_images/2977395#annotated) if anyone would care to help out with identifications, I'd be grateful?

For a Skywatcher StarTravel 80 with just a guide camera attached, you enter the focal length of the scope: 400. This is to give PHD2 the image scale. Just to make sure I've understood the question correctly, what extender are you referring to?

+1 for the 10mm studding. I had to replace the lock shaft on my EQ5 a while back. Two wing nuts, one plain nut and three repair washers from the local DIY store were all that I needed: If you want to be super neat, you could put a tube around the exposed threads above the oddments tray, but I haven't felt the need.