A320Flyer

Here is my effort using Pixinsight.

I think I might have over-processed this so here is a more subtle version. 

Bill

I use an ASI1600 on a SW ED72 with the OVL FF and have the same issue. I have gradually increased the spacing and am currently at 58.5mm. Stars are much better now with only the very edge stars showing elongation. I have read elsewhere that the sweet spot is 60mm. The problem is that CCD Inspector reports the curvature getting worse but I see the stars getting better. Try increasing your spacing. 
Cheers

Bill

Hi,

Would someone with this setup be able to advise on the optimum spacing distance they have in order to get round stars across the full frame of a ZWO ASI1600. 
 

I am having a bit of trouble dialling in the correct distance. I started at the quoted 55mm and gradually increased. I do see an improvement but am currently at 58.5mm and wonder how much further might be necessary. 
 

Thanks

Bill

Next clear night I'll make sure my guide scope is accurately aligned.

When I play the images through PI Blink, there is a consistent movement from left to right (RA), no stutters, no discernible up/down movement.

If PE was an issue, it would have "corrected" itself on each worm cycle. 

Dithering is random on both axes, so I would not have thought it would not have manifested itself as a consistent left/right movement.

My PA is pretty good as there is very little drift on DEC.

This particular target/imaging session was almost at Zenith, so I'm thinking DF would be minimal?

I have my mount East-heavy as this gives me much better guiding RMS and dither recovery. Could I have it TOO East-heavy? 

I'm using MaximDL multi-star guiding so I would have though at the start of each image, any RA drift would have been corrected as the guiding kicked back in?

I might try single-star guiding with/without Dither to see if that reveals anything.

Thanks for all your suggestions.

Bill

Hi folks,

I have noticed that there is a significant drift between the first and last images in an imaging session, even though I am guiding. I want to try an minimise this as much as possible.

For background information, for this particular session, imaging setup was:

ZWO ASI 1600 MM Pro, imaging through a SW ED72 on a HEQ5 Pro mount with belt mod. Guiding with a ZWO ASI 120mono via a SW 50ED Guide scope.

Image acquistion via MaximDL6, guiding via MaximDL6 using EQMod Pulse Guiding.

Guiding RMS was between 0.5 and 0.9 arcsec/px with a small dither of 1.0 pixels between each 300sec exposure and a settle criteria of 0.25 pixels and 15secs delay.

My  imaging camera is fairly accurately aligned with the long side of the chip in RA.

As you can see from the attached images, stars a pretty round but there is a significant drift in RA between Image1 and Image51.

As I understand things, MaximDL stops guiding between exposures to allow download of the image and then recommences guiding. With the above settle criteria, this is about 25secs between exposures.

Polar Aligned using Sharpcap with a PA error of less than 10sec.

Any suggestions or help would be very much appreciated.

Cheers

Bill

SHO combination in PI, Ha as luminance, finished in PS.

Bill

This is something I posted on CN as a reply to a post. I thought I'd post here as well in case it is of use to someone.

This a 3D-printed Camera Rotator I designed to fit my ZWO ASI1600 and ASI183 cameras.

The metal plate is a 76x15mm frame cramp (available here in the UK for about 15p each) screwed to the face of the flat section using small self-tapping screws.

To calibrate it (a one-time operation), attach it slightly loose to your camera (aligned roughly to either the long or short sides of the camera sensor), take an image, plate solve to find the angle, park your scope horizontally, attach the magnetic Wixey, rotate the bracket to set the matching angle, tighten up. Done

In your imaging/planetarium software, just input your sensor details to match if you aligned to either the short or long sides.

I have been using this on my refractor and newtonian for two seasons now and can achieve (much) less than 1deg rotational accuracy between successive imaging sessions. This is great when, here in the UK, it can be weeks between taking my Ha, Sii and Oii subs. 

I have attached the STL files if anyone finds it of use.

Cheers

Bill

Camera Inclinometer 78mm ID Part1 V1.0.zip Camera Inclinometer 78mm ID Part2 V1.0.zip

Here'my attempt. Processed mostly in PixInsight as SHO, with Ha as Luminance, then colour balance tweaked in Photoshop.

Bill

Internally, PI uses a Normalised Scale where 0 represents Black and 1 represents White.

So, your value of 500 is represented by 0.008 on the Normalised Scale.

$T is used to represent the pixel value of the active image.

So, your formula should be written as iif($T<0.008,$T,1)

Try that. 

Cheers

Bill

I just had to have another go at pulling out the Oiii

Bill

Here's my attempt using PixInsight.

Custom HSO combination.

Luminance stretched with HT.

HDRMT and LHE to bring out the details in the background and foreground respectively.

Combine Lum with SHO.

Cheers

Bill

Here's my attempt using PixInsight.

Basic SHO combination.

Curves to shift the tones towards the Hubble Palette.

SCNR to tone back the greens a little and to suppress the magenta stars (inverted image).

Ha as Luminance, stretched with HT and stars blended from a Masked Stretched version.

HDRMT and LHE to bring out the details in the background and foreground respectively (with suitable masks).

Combine Lum with SHO.

Image rotated and flipped to give conventional orientation of M16.

Cheers

Bill

Done! So simple!!

Hi

This is interesting. 
I have a 6 year old HEQ5 that has never been updated and I am currently experiencing guiding issues that I can’t seem to solve with tweaking guide settings. The SW website list two firmware downloads that look as if they would apply to an HEQ5: Motor Controller Firmware Loader V1.74 and HEQ5 Go To Mount V2.04. 
Is it fairly straightforward to do the update? Do you need both downloads? Do you use the serial cable that came with the mount? I have an old winXP laptop that has a serial port. Will the update work under winXP? 
Thanks

Bill

Hi Dave

Welcome to SGL. 

I’m a member at WYAS and, as previously mentioned, we are open Tuesdays and Fridays. We are a friendly and welcoming bunch with many doing visual observing and a small, but active, group of imagers.  We do an astronomy beginners course on a Friday and I believe one is due to start in the next couple of weeks.

I go most Tuesdays so if you do pop down, ask for me and I’ll introduce you around. 
 

Cheers

Bill

I just PM’d you. 

Thanks guys.

Hi

This is a 300sec dark frame from my new 1600MM-pro. Compared to my 183MM-pro, there is a LOT more hot pixels, so much so that they show up as a second peak on the histogram. Is this normal? 1600 and 183 Dark Frames attached for comparison.

Thanks for any help.

Bill

Hi guys. Thanks for all the responses. In the end, I simply removed the collar on my mpcc which allows it to be pushed further down the draw tube. To now get focus I have to rack the draw tube out a bit which has cured the nibbles. 

Bill

Hi folks

I own a SW150P which I use with a ZWO183MM Pro/Filter Wheel/ Baader MPCC. With the correct 55mm spacing to the CC, I need to rack in the focus tube to get focus. This means I get horrible little “nibbles” taken out of my stars where the focus tube interferes with the light path. I’m thinking of “upgrading”to the 150PDS as I understand that the primary mirror is set nearer the focus tube to avoid this. Can anyone confirm? Will I still get the “nibbles” with this combination?

Thanks

Bill

I asked the same thing on the ZWO forum. Check out the responses.

https://bbs.astronomy-imaging-camera.com/viewtopic.php?t=8600

It can be done using the native driver for the third camera. 

Bill

Try inverting the image (the purple become green), use SCNR to reduce the green, then re-invert the image. 

Bill

Guys,

An update on my second night with PHD:

I spent ages getting good PA then I tried increasing the Max Dec Duration up to 1500 as suggested. This made the "saw-tooth" motion on the Dec graph worse. As I am using a 50x9 finder-guider on an eq3-2 mount, the slowest speed of the guiding motors is 2x sidereal. So, logically, I thought "if my motors are running faster than the ideal speed, I should reduce the Max Dec Duration so that the guiding is not so severe". I reduced this to 300 and saw an immediate improvement in the shape of the Dec graph. I then fine tweaked the settings to RA agr =5 0, RA hys = 10, Mn mo = 0.10, Max RA = 1000, mx Dec = 450 and Dec guiding left at Auto.

This gave me a fairly even graph and no noticable trailing in 5 min subs.

As I said, this is for a guider-finder on an eq3-2 mount. It works for me and I hope it might be useful to someone else.

Thanks for all your help.

Bill

Hi Guys,

I certainly dont want to hijack this thread but I too would also like to know the answer to this. I tried giuding for the first time last night and got pretty much the same graph as Danny. RA and Dec seem to guide very well then, suddenly, Dec takes a dive then recovers slowly. All is ok for a couple of minutes then the dive again.

Could this be anything to do with backlash? and if so, how to rectify?

Cheers

Bill