alan potts

1 minute ago, Adreneline said:

There are far worse ways to part with cash - and at my age you can't take it with you!

Enjoy while you can!

I found a way, asbestos suite cases.

1 hour ago, Adreneline said:

!!!!!!!!!

Well I envy you so much Alan. The most I've ever managed since taking up AP is four consecutive nights - clear and with no moon!

I need to repeat the test with the mount using my WO-ZS71+ASI1600 and maybe the ED80DS-Pro. If I can image without guiding then in theory I can stay within the payload limit for the mount, although to be fair I rarely use the ED80 these days.

The 60 and 120 look great to me but with what I use I don't need that sort of payload capacity or weight.

Good luck!

Adrian

My worry about the 120, is I keep looking at the 12 inch SC and thinking de-fork, even though every man and his dog have told me don't do there. The 60 would be a cheaper option but maybe too small for decent work with the SC which weights about 17-18kg, which of course whould not matter with the CEM 120. What is is about this hobby that forever makes us want to part with cash.

Alan

A very good question I don't have an answer to, I have cleaned all my system and still have them, personally I feel they hang in the air.

Alan

Very pleased all went well for you, I have told FLO where to put clouds and they clearly miss read the sentence and sent them to you as I have had about 35 days clear now and I have taken a delivery and expecting another, we actually need clouds and rain. Keep looking at these mounts and I have to say I am very tempted, it is just the 60 or the 120 I need to come to terms with.

Alan

I don't use Polemaster but there appears to be something wrong here. You have to take this up with FLO, they will see that what ever it is is put right in which ever way, but I am sure in the end you will be happy apart from the wait I guess. I am no expert but the guiding does not look what I would call good.

Alan

I had a strange night where I tested EQmods PPEC and PHD's PPEC, alone and together and found the various different subsections of the PHD, I actually found the default normal running in PHD with EQmod's PPEC to be the best. 

Different scopes and cameras but I never went above 1 sec deflection on either RA or DEC, most of the time it was around 0.5 mark or better, in the seconds section, I don't actually know what RMS means, it did go out of these lines in Dither though. . The odd thing is even when what appears to look bad to me, I can never see it in the stars when I view the sub, so I guess not much is wrong and I am being somewhat compulsive.

Interesting to have chatted about this and something to play with more when the Moon is out and about. However the more I look at this the more I feel it comes down to quality of seeing as a few night ago without changing anything from the night before I had almost straight lines, so good in fact for a few occasions I thought it had stopped working.

Alan

Mike some how you managed a duplicate post, so I have deleted one, nice images in these shots!!

Alan

Nice image Francis, I can still get on this if I get the chainsaw out and cut a walnut tree down, I feel this may be easier than taking a house out. Watching you work closely as I am thinking hard about a CEM 60 or 120. I see you corners appear nice and round, something I am not getting with my .79 reducer fitted which gives me about 638mm. not sure what I can do as it states 55mm back focus and with fitting I should get exactly that, can't believe the extra 5mm make such a difference, in any case how can I go shorter than 55mm without getting the hacksaw out.

Alan

Good to see you have the new mount up and running, who knows maybe the clouds will clear off now, good start on the bubble, not an easy target I wouldn't think, did you see Olly's work on this.

Alan

5 hours ago, JamesF said:

I wonder if the spacing might be out slightly then.  I have the 2" version and whilst I haven't used it yet because I didn't have the right spacers to get the correct backfocus, it does appear to vary quite a bit with the focal length of the OTA.  They give a table of backfocus distances on the web pages for each reducer, but I suspect they're only actually guidelines and that experimentation may be required to find the exact distance.  What OTA are you using?

As already suggested, I think I would be trying all the usual stuff like rotating the camera, rotating the camera and reducer, trying a different camera, even rotating the telescope if that's possible, to try to identify what is causing the problem.   Like the ASI1600 microlensing issue, it may be a specific combination of kit or something specific to the positioning of it that combines to give you a problem that you wouldn't otherwise see.

James

Mine is 805mm and I sort of thought 5mm wouldn't matter too much, Dave had a look around and said there were others with problems and were being made to jump through hoops to prove it, which sound like this outfit judging by experiences I have had.

Alan

A totally stunning image you have created there. Would you tell me in brief how you join frames as a mosaic, I would like to try say the NA Neb but can't fit it into my FOV at 800mm.

Alan

13 hours ago, JamesF said:

Is this the TSRed 279 reducer, Alan?

James

Yes James the large one for 3 inch focusers, not very impressed, it is a good job I didn't buy it new.

Alan

6 hours ago, symmetal said:

I wasn't aware of the PHD2 PPEC and will give it a try next time. It sounds useful.

The Eqmod PEC once recorded is applied continuously from then on while tracking. This requires the PEC corrections to always know the current phase of the worm gear cycle. If these get out of step by the mount getting knocked or manually slewing with the mount off, the PEC corrections then get applied in the wrong place making things worse. This happened to me a couple of times and having to record the PEC again is a pain. There was no way of knowing if the PEC was in or out of phase so I never bothered with it again. This was a few years ago. Whether it is better now and can keep itself in step better I don't know.

The PHD2 PPEC looks promising as it's reset for each new target. After learning the PEC corrections over 2 cycles (while imaging so no time lost) it is applied only while imaging that target. It also handles dither OK. If you then slew to another target, it starts the PPEC learning process over again so it doesn't need to keep track of the phase of the worm cycle so won't get out of step.

You can therefore use both PEC corrections together as almcl says, as the PHD2 PPEC will just correct for the errors left over after applying the Eqmod PEC.

Alan

Yes Alan, something I was not aware of, there is a whole box of toys there to have a play with, I think I will be giving the a try, I am reluctant to mess too much as guiding is fairly decent, if I could get rid of the odd blip, which in truth don't often show in star, things would be very nice.

Alan 

7 hours ago, almcl said:

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?

All very confusing, there is also a PPEC within EQmod as well which I briefly describe above. I am going to give the PHD2 version a try in any case. My guide with the PPEC in EQmod seems to be better than without it so I am sure it does something.

Read the Sky Watcher manual it would appear to be very much the same. Over all my guide is fairly decent, it just has the odd blip that would be nice not there.

Alan

Stub,

This was something that some one touched upon the other day, I have to confess I have never seen it before though did hunt down the area in PHD without understanding anything, nothing new there. This is yet another to read up on.

The PEC I was looking at and the PPEC that I am using sits in EQmod. PEC is a run of 5 and upward rotations of the worm recorded in the opening control panel of the program, you get to the various sections by clicking on the Green Cross on the upper left hand side. This can create a file that can if you wish be doctored in PECprep, another program, this seems a fair bit more advanced than I am comfortable with at the moment.

The PPEC I am actually using, if indeed I am using anything at all other than imagination, sits int he open out menu EQmod on the far right hand side. This has a record/play refresh section, dependent upon whats happening in the routine running list will pulse the mounts LED, 1,2 and 3 time, 3 times meaning it's running.

Maybe this is interlinked in some way to PHD2 PPEC, but I feel the PEC section is EQmod specific and is stand alone and in no way connected.  I was going to have a go tonight but it was patchy cloud.

Alan 

For everyone, just out of shot is Sadr, fairly bright, here are 25 stacked 4mins images and some actually had Sadr in them, which I cropped. Same telescope, same reducer, same camera position, only I was a few days younger.

Alan

1 hour ago, rockinrome said:

Is this a slight imperfection/crack in the glass that the eye cannot see ...??
 

Well that is sort of difficult to trace, one would hope not, can't see anything but I am having a better look later on.

Alan

1 hour ago, Stargazer33 said:

Is there something loose in the TS reducer/flattener that possibly causes slop when you're imaging near the zenith? 

I will check but I do not believe this to be the case, but no harm looking.

Alan

1 hour ago, Ruud said:

No Idea what's going on, but you have triple arcs. I traced them and tried to determine their relative radii. The arcs  look like reflections of each other. That they're not the same size would indicate reflections off curved surfaces. 

For a moment I thought the centres of the circles formed a right angle, but they do not.

I hope you can sort this out soon.

Interesting piece of work there and thank-you for taking the time, I personally feel this reducer is a piece of junk, best not put stronger. Dave has google this and it would appear I am not on my own but I will just have to lump it. Here is another shot not as bad from last night, withing a tad the same place, glutton for punishment, I am sure you can see from this the corners are rubbish too, near 300 pound new this, and as poor as I am at this AP game, Canon camera and 55mm back space with only one fitting for the camera and threads all around, difficult to get wrong. BTW guide was decent.

Alan

3 minutes ago, Stub Mandrel said:

Predictive PEC on RA and Resist switch on DEC. Recently I've had constant 0.65"  with the 130P-DS which is (according to Vlaiv's calculations) as good as the HEQ5 (or an EQ6) can be be expected to deliver because of the step size.

I PA with Sharpcap, typically to better than 0.2'.

The heavier 150PL I get slightly higher figures.

I am running the PPEC now but I thought this stood for Permanent, wrong again. I was to try the minimum 5 turns of the worm PEC.

Alan 

Superb image and another commitment to data, 25 hours could be more than I did all August and every night was clear, though time out for the Moon. Not an easy target I am sure.

Alan

Excellent image, I see you must have used it wide open as it doesn't have those annoying blade artifacts, I have a F2.8 and and F 4 Canon lens, I stopped down a stop using the F4 (it hasn't been used for years) doing this put me off it all together.

Alan

1 hour ago, wesdon1 said:

That sounds a very plausible scenario with the flattener? You could try a process of elimination, and when/if it is the flattener, try contacting manufacturer for advice? From my experience with photography, it's often a whole host of different reasons why an image can have imperfections/distortions etc. Light can do strange things when we play around with it! lol How did your Wednesday session turn out? did you get to the bottom of it? 

Wes.

No sort of got nowhere fast, thought it was some marks inside the sleeves caused by something, covered them with matt black paint and still the same but not as bad, the smallest movement seems to make it go away so it's internal reflections of some type, poor for what this would cost new.

Alan

12 hours ago, Stub Mandrel said:

I use it now, it's really easy. I haven't made any exact measurements but I see my guiding improve over the first twenty minutes to half hour and I am definitely seeing better guiding since I started using it.

For the DEC I find that 'resist switch works best.

SM, can you tell me which one you actually use and briefly how. I had a read and took some subs last night and found it a little confusing, not difficult for me, there seems to be a few ways to skin a cat.

I think I will try for automated one and auto load, but then as I get more confidant try to doctor the file in PECprep, which I see you can do, this guiding can get a bit obsessive, most of last night I was below .5 sec or something like .3 pixel, but them every now and then, with no real pattern, bang, a spike at 1sec plus, on Dec mainly and my PA is under 1min. That is according to Polar align and guide assistant. Most of last night Dec was a straight line.

Alan

15 hours ago, Ibbo! said:

The shiy bits more than likey produced the arcs in your image.

The t adaptors can vary in length esp the cheap ones have you any very thin spacers to slighty increase the distance and see if that makes a difference.

 

Apart from that I am out of ideas.

No I don't have such but thought of it, the matt black paint didn't help either, it is still there when very close to Deneb, but not the same,  internal reflection of some sort for sure. Maybe just have to put up with it, turn the camera a tad and run new flats. Not the end of the world but very poor for a piece of kit costing almost 300 quid, and I'm sure it is the reducer.

Alan