Stuart1971

That’s a cracking image for just 1 hour 20mins…👍🏼 What filters did you use…?

Yes, that’s perfect for this set up, nice big pixels….and a good 1/2” sensor…👍🏼

I see no reason why not, plenty of back focus on the edge to get close, then fine focus with the Baader, OAG’s commonly used with SCT…I would say all good… I have used a similar set up with a Meade 8” SCT without issue You may need a really sensitive guide camera though with an OAG at those SCT focal lengths…the ASI174m mini is an excellent choice…👍🏼

It’s only in the top right and left corners though, surely it would show all over if a collimation issue….🤔

Hi all, I have a Tak FSQ85 scope being used with a QHY268c camera, and am getting some odd star shapes just at the top of my images, both right and left corners, they look almost like thick crosses, or diffraction spikes… now on the bottom left and right corners I get a slight star elongation, so would these two things be a sign of an issue such as sensor tilt or such like…? image below, of top left corner…

And that’s not confusing, 11.31 x 11.31 is not 1” diagonal….it's 16mm🤔🤔, so yes that is totally confusing….. I mean c’mon 1” class, what does that mean, many people have no idea….

You are correct and it’s totally confusing to anyone who does not understand, of which I am one of, I have had this discussion recently with QHY as they are advertising there new 533 mono camera with a 1” square sensor, which it a total misrepresentation, why can’t they just just put 16mm diagonal, it’s far easier to understand, it’s no where near 1” square…but to a newcomer or even someone who has been in the hobby for years, sees this and thinks wow 25mm x 25mm sensor, only to receive and find its approx 11mm x 12mm 🤔🤔

Sorry to read this, especially as I have been considering a retirement present to myself of one of these mount….so watching with interest….🤔

Ok….Dr Vlaiv…👍🏼

Ok, so,it’s a CCD, different story…..any length flats you like, as @vlaiv says use the ones that work…..👍🏼

I did say, CAN cause issues….👍🏼

Hmmm, have to disagree, as long as you send Royal Mail tracked service if it goes missing you can claim from Royal Mail, this happened to me once, and I had a successful claim, even though it was lost overseas with a partner service….you need to pay for a Royal Mail tracked service though…👍🏼

Do an online quote for the postage with the full camera cost….actually with Royal Mail special delivery and extra insurance it will me much cheaper than that, but with a courier no, will be more expensive…

If it’s a CMOS camera, then you need flats between about 3-5 seconds, any shorter and they can cause issues….

What are the different ways you are trying, I use dynamic brightness with 4 second exposures with an ADU of approx 26,000 and they work perfectly, with my QHY268c

If it gets lost and you have to claim, you will only get the cost you declared the item is worth….so think about it….🤔 Assuming you will insure…if you choose to insure for the full value, it will cost around £150 to send….

Is does not show the gain and offset because it’s a CCD camera and not a more modern CMOS version, the gain is never shown in the drivers of a CCD camera, it’s preset in the camera firmware and can’t be altered….

After you change the guide rate back to 0.5, you have to re calibrate anyway, don’t try and guide without doing that, also when entering your pixel size and focal length into PHD, it should work out the step size needed for calibration, also set where in the sky you will do the calibration, should be just due south at 30 degrees is best…👍🏼 you should not have anywhere near 51 steps, that’s the highest I have seen….Should be set at 12, and it should take between 8 and 12 normally…

There is a an error in the video, you talk about how you mount had bad RA backlash when you used it the first time, and you show the graph of this from PHD, but the graph you show is DEC backlash and not RA, there is no RA backlash graph in PHD as backlash in RA is not really an issue….so I think you get mixed up as you are adjusting the belt tension in DEC but talking and saying that it’s the RA drive that it’s bad on and then showing the DEC backlash graph, personally I got very confused….🤔🤔 apart from that very good

This is mine, yes a lot of backlash as it’s an old EQ8 mount, (it’s been adjusted out since this calibration some time ago) but before and after the change of direction at the top, the red lines are perfectly straight as they should be, as the gears are engaged and going in the same direction…I think I would check yours out….

This concerns me, especially on a mount that has supposed to have been hyper tuned….these yellow circled steps that are out of line, this could be slippage, or something loose somewhere….this red line should be perfectly straight, after the direction change at the top, where it shows the backlash, the line coming down should then be again straight….

Well the amount of calibration steps, is due to the low step size too, he maybe could just up that as well as up the guide rate…

Yes my mistake….👍🏼

When you guide in RA the mount is moving a sidereal rate 1 arc second per second, if your guide rate is set at 0.5 then when you need to pulse in the west direction, it means you actually speed the mount up by the guide rate amount, so your pulse will be at 1.5x sidereal, when you guide east it will slow it down by the amount of your guide rate, so the pulse will be 0.5x, the RA is moving all the time, and alters with guide pulse's but never stops or goes in the other direction….

Sorry to disagree, but 0.8 is too high, and far too aggressive for this mount, 0.5x is the norm also 0.8x does not equate to 8 arc seconds per second, the guide rate is a fraction of sidereal rate, and sidereal is 15 arc second per second