334 replies to this topic

[SKhan]

Does anyone know here to interpret PHD2 logs from ASIAir Plus? I can share the link so that i can receive appropriate advise on how to fix the guiding problems.

[BoydUtah]

Although all the dealers are still listing the OTA as a "RedCat 91 WIFD,"  William Optics itself appears to have switched the name to "Cat 91 WIFD."

 

https://support.will...cts/cat-91-wifd

 

Ditto all the other "Cats," except the '51, '61 and '71 that are bundled with ZWO mounts.

 

Chen

Yes, Karen at William Optics confirmed that they have switched from "RedCat" to "Cat."  

[BoydUtah]

My son Reynold and I also took delivery of a Cat 91 and shot a couple of unboxing and spec videos, linked below.  Folks on this thread have said a lot about the spot sizes of the Cat 91.  Attached is a comparison of its spots with those of the Cat 71 and Tak 106.  Based on this comparison, the Cat 91 is in a league of its own, so we're excited for the clouds and full moon to disappear so we can get some images and see how well it actually performs with our ASI 6200 MM Pro camera.  Here are the links to our videos:

     https://youtube.com/shorts/U5-3OE1IOag
     https://youtu.be/6CY6tjgaBWM

[AstroFritz_]

Hmm, I'm wary of the this fifth element (pun intended) that doesn't move with the other 4.   Hearing this so far, I'm learning toward just RC71, with traditional 4 elements, because I know it does not have back focus issues (I've owned it before) and only has the traditional 4 elements, so once it in focus, its a clear image, and I've never used or owned BXT and those other software.  All four elements move with the focuser.   You can see my RC61 and RC71 pics posted on this website and never have used BXT on them and the pics are very sharp and clear.    I love these two models. 

When they say that its and petzval style scope then it should have, when its in focus, a flat field when you are in the "range" of backfocus.
My FRA300 by Askar had 45-65mm range when its used with the T2/M48/M54 adapters.

The 91mm Cat should work simular.

 

When they claim the scope as an petzval style scope and it has no flat field then they should mentioned it in the description of the scope or manual.

When that is not the case I would say its a scam.

Otherwise scopes like the Pleiades or some Askar would be a better buy.

 

 

@SKhan
Can you make a 300s frame without a DNB filter on with the Cat?
You cant see the real performance with such a filter.

[Foobaria]

When they say that its and petzval style scope then it should have, when its in focus, a flat field when you are in the "range" of backfocus.
My FRA300 by Askar had 45-65mm range when its used with the T2/M48/M54 adapters.

The 91mm Cat should work simular.

 

When they claim the scope as an petzval style scope and it has no flat field then they should mentioned it in the description of the scope or manual.

When that is not the case I would say its a scam.

Otherwise scopes like the Pleiades or some Askar would be a better buy.

 

 

@SKhan
Can you make a 300s frame without a DNB filter on with the Cat?
You cant see the real performance with such a filter.

I would not recommend Pleaides. 

[AstroFritz_]

I would not recommend Pleaides. 

You mean the 68mm right?

 

I tested the 111mm one with a friend for two nights.
The optic was really good.
But we didnt buy it because it has no variable backfocus likte the Cats.

[Foobaria]

You mean the 68mm right?

 

I tested the 111mm one with a friend for two nights.
The optic was really good.
But we didnt buy it because it has no variable backfocus likte the Cats.

Yes 68, haven't tried the 111.

[w7ay]

Pls can you check and advise - i have already shared two images: one for each of Rosette and North American Nebulae.

 

https://1drv.ms/f/s!...9eyI2s_Joi-cdGQ

 

I took a look at the raw North America Nebula one (since it is more recent) and the tilt does not look terribly bad at all, out of the box.
 

 

There is about a 9% tilt along the long axis of the sensor.    Something like BlurXTerminator should take that kind of tilt out almost completely.  Unless you are OCD or not willing to use BlurXTractor, you can just leave the tilt adjustments alone.  (Crossing my fingers that mine will be similar.)

 

Your already nice image appears to be limited by the mount, and not by the OTA. The better OTAs are so sharp that they show up the flaws that you may never have noticed with bloated stars from something like the RedCat 71.   I will be putting mine on an RST-135e which autoguides with ASIAIR to better than 0.35" RMS when there is no wind) -- but then I guide with an FMA180pro with an ASI678MM and the Astronomik 742 IR pass filter to avoid the blue parts of the spectrum that is more affected by atmospheric turbulence, so my mount will likely not be the limiting factor.

 

Anyhow, this appears to confirm that W.O. is getting better at QC (you should have seen the tilt on my WhiteCat 51).  The Pleiades 68 was the first indication -- coming from the existing Takahashi FSQ-85 and FOA-60Q,  I was floored by how well the Pleiades performed that I ordered the Cat 91 sight unseen, based just on the published spot diagrams for the Cat 91.

 

Chen

Edited by w7ay, 17 November 2024 - 07:27 PM.

[w7ay]

Separately, What is RMS as you mentioned in your comment?

 

I think she means the root mean squared (RMS) radius of the point spread function spot.  "RMS" is simply the square root of the average (mean) error of the square over multiple data (radii) points, or equivalent to the standard deviation in probablility theory.  Before taking the square root, the mean squared number is just the variance in probability theory.

 

Without context, "RMS" has no meaning, of course, since it can be an RMS voltage of an AC signal, or the RMS angle in arcseconds of an autoguiding error (in the case of autoguiding, where the total RMS error is simply the square root of the RA error squared, summed with the declination error squared, and also averaged over time.

 

But since we are talking about the spot diagram, I think she must mean the RMS of the spot radius.

 

The spot radius also depends on the wavelength.  This for example is the spot diagram of the Baby-Q with the 1.01x flattener that associates each color of the spot to a wavelength:

 

 

So, the RMS value will be the RMS of the spot diagram for all wavelengths.

 

Take a look at what @BoydUtah has posted earlier -- notice how much larger and bloated the spot of the Cat 71 is at the longer wavelengths.  This will for example cause stars to have a red halo.   In the case of the Baby-Q's spot above, it is the blue side of the spectrum that develops a larger spot, but not as bloated as the red in the Cat 71.

 

Many spot diagrams will show more useful actual numbers, instead of the "look shiny" diagrams, like as shown at the bottom of the spot pictures for the Cat 91 here:

 

 

The 6 colums at the bottom relates to the 6 diagrams, i.e., column 1 is a spot at the optical center, column 2 is a spot that is 6.48 mm from the center, etc.  Your APS-C camera's corner is about 14mm from the center, so we would expect the spot radius at the corner of your camera to be between columns 3 and 4.  Essentially, a near perfect OTA.  Once day, someone with the ability to, will publish the Strehl numbers for the Cat 91.  I'll bet it is close to, or beats, the current best Strehl amoung hobby telescopes - the FOA60Q.  And the Cat 91 does it at f/5 instead of f/15 for the FOA60Q.

 

Just like the RMS value for autoguiding, the RMS radius is an average.  You will find that the worse case deviation will be worse -- a sine AC waveform has peaks which are the square root of 2 larger than the RMS voltage, for example.  Similarly, the red spot radius of a Cat 71 is much worse than the RMS spot radius, which had averaged in the smaller blue spot.  

 

Another thing to look for whan evaluating scopes before plopping down your hard earned money is the "GEO Radius" that can also be seen in the Cat 91's spot diagram.  This is probably more honest since the GEO radius is something closer to the worse case: i.e, with the Cat71, it would be the radius of the red spot.

 

Recall that your ASI2600 has a pixel size of 3.76 µm.  So, a GEO Radius of 2.96 µm at the optical center of the Cat 91 says an ideal spot (no manufacturing flaw, no atmospheric turbulence, no tilt, perfect alignment of lenses, etc) has a diameter that is about 1.6 times the pixel size of your camera.  Most likely though, atmospheric turbulence alone will be larger than this.  Notice that the HFD ("d" being diameter) of the center of the tilt diagram is about 3.8 times the pixel size, and if you had focused well, it means that atmospheric turbulence (the 3.8x pixel size) is limiting the star diameter, and not the OTA (1.6x pixel size). 

 

You have a good scope.  Keep it! :-).

 

Chen

Edited by w7ay, 17 November 2024 - 08:54 PM.

[Foobaria]

Thx.  If you look at the number for field 1, its 1.399 at scale 100, and for 71 its 3.124 for the same scale. I would assume this means it has a sharper result (i.e., the number is smaller for RC91). 

[SKhan]

I took a look at the raw North America Nebula one (since it is more recent) and the tilt does not look terribly bad at all, out of the box.
 

Screenshot 2024-11-17 at 1.14.57 PM.jpg

 

There is about a 9% tilt along the long axis of the sensor.    Something like BlurXTerminator should take that kind of tilt out almost completely.  Unless you are OCD or not willing to use BlurXTractor, you can just leave the tilt adjustments alone.  (Crossing my fingers that mine will be similar.)

 

Your already nice image appears to be limited by the mount, and not by the OTA. The better OTAs are so sharp that they show up the flaws that you may never have noticed with bloated stars from something like the RedCat 71.   I will be putting mine on an RST-135e which autoguides with ASIAIR to better than 0.35" RMS when there is no wind) -- but then I guide with an FMA180pro with an ASI678MM and the Astronomik 742 IR pass filter to avoid the blue parts of the spectrum that is more affected by atmospheric turbulence, so my mount will likely not be the limiting factor.

 

Anyhow, this appears to confirm that W.O. is getting better at QC (you should have seen the tilt on my WhiteCat 51).  The Pleiades 68 was the first indication -- coming from the existing Takahashi FSQ-85 and FOA-60Q,  I was floored by how well the Pleiades performed that I ordered the Cat 91 sight unseen, based just on the published spot diagrams for the Cat 91.

 

Chen

Thanks Chen. Is that tilt something fixable in the hardware rather than the BXT? And separately, it seems that the guiding problem is stemming from the mount, how to fix it?

 

Did you plate solve this image? Which software did you use?

 

SAK

Edited by SKhan, 17 November 2024 - 09:39 PM.

[SKhan]

When they say that its and petzval style scope then it should have, when its in focus, a flat field when you are in the "range" of backfocus.
My FRA300 by Askar had 45-65mm range when its used with the T2/M48/M54 adapters.

The 91mm Cat should work simular.

 

When they claim the scope as an petzval style scope and it has no flat field then they should mentioned it in the description of the scope or manual.

When that is not the case I would say its a scam.

Otherwise scopes like the Pleiades or some Askar would be a better buy.

 

 

@SKhan
Can you make a 300s frame without a DNB filter on with the Cat?
You cant see the real performance with such a filter.

Yes can do but it has to be the next week or the week after.

[SKhan]

I think she means the root mean squared (RMS) radius of the point spread function spot.  "RMS" is simply the square root of the average (mean) error of the square over multiple data (radii) points, or equivalent to the standard deviation in probablility theory.  Before taking the square root, the mean squared number is just the variance in probability theory.

 

Without context, "RMS" has no meaning, of course, since it can be an RMS voltage of an AC signal, or the RMS angle in arcseconds of an autoguiding error (in the case of autoguiding, where the total RMS error is simply the square root of the RA error squared, summed with the declination error squared, and also averaged over time.

 

But since we are talking about the spot diagram, I think she must mean the RMS of the spot radius.

 

The spot radius also depends on the wavelength.  This for example is the spot diagram of the Baby-Q with the 1.01x flattener that associates each color of the spot to a wavelength:

 

FSQ85_Spot Flattener with scale 5K.jpg

 

So, the RMS value will be the RMS of the spot diagram for all wavelengths.

 

Take a look at what @BoydUtah has posted earlier -- notice how much larger and bloated the spot of the Cat 71 is at the longer wavelengths.  This will for example cause stars to have a red halo.   In the case of the Baby-Q's spot above, it is the blue side of the spectrum that develops a larger spot, but not as bloated as the red in the Cat 71.

 

Many spot diagrams will show more useful actual numbers, instead of the "look shiny" diagrams, like as shown at the bottom of the spot pictures for the Cat 91 here:

 

Diagram_Cat-91_1.jpg

 

The 6 colums at the bottom relates to the 6 diagrams, i.e., column 1 is a spot at the optical center, column 2 is a spot that is 6.48 mm from the center, etc.  Your APS-C camera's corner is about 14mm from the center, so we would expect the spot radius at the corner of your camera to be between columns 3 and 4.  Essentially, a near perfect OTA.  Once day, someone with the ability to, will publish the Strehl numbers for the Cat 91.  I'll bet it is close to, or beats, the current best Strehl amoung hobby telescopes - the FOA60Q.  And the Cat 91 does it at f/5 instead of f/15 for the FOA60Q.

 

Just like the RMS value for autoguiding, the RMS radius is an average.  You will find that the worse case deviation will be worse -- a sine AC waveform has peaks which are the square root of 2 larger than the RMS voltage, for example.  Similarly, the red spot radius of a Cat 71 is much worse than the RMS spot radius, which had averaged in the smaller blue spot.  

 

Another thing to look for whan evaluating scopes before plopping down your hard earned money is the "GEO Radius" that can also be seen in the Cat 91's spot diagram.  This is probably more honest since the GEO radius is something closer to the worse case: i.e, with the Cat71, it would be the radius of the red spot.

 

Recall that your ASI2600 has a pixel size of 3.76 µm.  So, a GEO Radius of 2.96 µm at the optical center of the Cat 91 says an ideal spot (no manufacturing flaw, no atmospheric turbulence, no tilt, perfect alignment of lenses, etc) has a diameter that is about 1.6 times the pixel size of your camera.  Most likely though, atmospheric turbulence alone will be larger than this.  Notice that the HFD ("d" being diameter) of the center of the tilt diagram is about 3.8 times the pixel size, and if you had focused well, it means that atmospheric turbulence (the 3.8x pixel size) is limiting the star diameter, and not the OTA (1.6x pixel size). 

 

You have a good scope.  Keep it! :-).

 

Chen

Does it mean that Cat 91 will exhibit less of a chromatic aberration at the edges compared to Tak?

[w7ay]

Thx.  If you look at the number for field 1, its 1.399 at scale 100, and for 71 its 3.124 for the same scale. I would assume this means it has a sharper result (i.e., the number is smaller for RC91). 

As long as atmospheric turbulence is not too horrible.  If "seeing" is bad, it can become the limiting factor on star size.  

 

 

Chen

[w7ay]

Does it mean that Cat 91 will exhibit less of a chromatic aberration at the edges compared to Tak?

Yes.  If my Cat 91 comes out as good as yours, I will be retiring my FSQ-85.  

 

And that is in spite of the fact that the Cat 91 is faster than the FSQ-85 at its native focal length (f/5.45).  Not a huge deal -- 25% less integration time, but better nevertheless.

 

The FSQ-85 with the 1.01x flattener is good only a little past APS-C.  It really does not do well at full frame unless you use BlurXTerminator.  Granted, someone still has to run the Cat 91 with a full frame, monochrome camera.  But, already, at APS-C, the stars from your Cat 91 look better than the stars from my FSQ-85 with the 1.01x reducer (457mm focal length) at APS-C.  Plus, if you look at images that are taken with the FSQ-85, you will always see the "inverse lighthouse" effect for stars not near the center (caused by aperture vignetting, producing a non-symmetrical aperture function).  Your stars so lar look clean to me.  BlurXTerminator gets rid of most of the "inverse highthouse," but not all.  I guess Mr. Croman did not train his neural net with FSQ-85 images :-).

 

For shorter focal lengths, I have already stopped using the FSQ-85 even with the new (RD-QB) x0.73 reducer from Takahashi, and using the Pleiades 68 in its place.  The Cat 91 may make me mothball the FSQ completely, even though the Baby-Q was my favorite OTA just 6 months ago, after zillions of OTA.  My first telescope was a 5" Newtonian whose mirror I had ground myself back in the mid-1960s when I was in secondary school in Kuala Lumpur.

 

Oh, by the way, you did not mention an electronic focuser.  On my Pleiades 68 and MiniCat 51, I had to mount a ZWO EAF on the fine focuser shaft of the WIFD, otherwise the horrible backlash from the ZWO EAF eats you alive with the "normal" focuser gear ratio of their WIFD.  I suspect I will have to do the same with the Cat 91.  

 

Chen

Edited by w7ay, 17 November 2024 - 10:56 PM.

[Tulsa]

Anyhow, this appears to confirm that W.O. is getting better at QC (you should have seen the tilt on my WhiteCat 51).  The Pleiades 68 was the first indication -- coming from the existing Takahashi FSQ-85 and FOA-60Q,  I was floored by how well the Pleiades performed that I ordered the Cat 91 sight unseen, based just on the published spot diagrams for the Cat 91.

 

Chen

I am waiting with bated breath for your opinion of this particular scope.  I have been reading and learning from your posts here on Cloudy Nights and the ZWO board.  Your opinion, experience and explanations are valuable to me.  Owning only a WO 81 doublet, it was all that was available during the pandemic in any consistent supply, I’m looking to upgrade and don’t wish to waste money with only advertised spec sheets to evaluate.  Thanks for sharing your knowledge.  

[w7ay]

I am waiting with bated breath for your opinion of this particular scope.  

Keep your eyes open for posts from @BoydUtah.  He already has a Cat 91 on hand, plus a full frame, monochrome camera.  And he probably does not have to wait for the rains to stop in the Pacific Northwest rain forest that I am stuck in :-).  

 

Just beg him to post unprocessed shortish exposures of star fields with a Luminance filter (to see GEO radius) and Blue filter (since that seems to give the smallest RMS radius with the Cat 91), instead of nebulas with long integration time/stacking, and post processed through BlurXTerminator :-).  

 

Chen

Edited by w7ay, 17 November 2024 - 11:39 PM.

[BoydUtah]

Keep your eyes open for posts from @BoydUtah.  He already has a Cat 91 on hand, plus a full frame, monochrome camera.  And he probably does not have to wait for the rains to stop in the Pacific Northwest rain forest that I am stuck in :-).  

 

Just beg him to post unprocessed shortish exposures of star fields with a Luminance filter (to see GEO radius) and Blue filter (since that seems to give the smallest RMS radius with the Cat 91), instead of nebulas with long integration time/stacking, and post processed through BlurXTerminator :-).  

 

Chen

Chen, my son Ren and I will be more than happy to comply.  Clouds are predicted in northern Utah for the next few days, but we'll take out the Cat 91 at the first opportunity.  By "shortish" exposures, what do you mean?  30 seconds?  1 minute?  3 minutes?  We were thinking of shooting M31 using our Antlia LRGB filters.  Would that work as a target, or would it be more helpful if we shot a richer star field somewhere in the Milky Way?  And am I correct in assuming that folks would like to see raw, unprocessed, unstacked, single frame images, rather than images that have been stacked, noise exterminated, and blur exterminated?  Would you be interested in FIT files or JPEG files?  And I'm assuming that folks will want us to post Bin 1 files to capture as much detail as possible, right?  

[SKhan]

Yes.  If my Cat 91 comes out as good as yours, I will be retiring my FSQ-85.  

 

And that is in spite of the fact that the Cat 91 is faster than the FSQ-85 at its native focal length (f/5.45).  Not a huge deal -- 25% less integration time, but better nevertheless.

 

The FSQ-85 with the 1.01x flattener is good only a little past APS-C.  It really does not do well at full frame unless you use BlurXTerminator.  Granted, someone still has to run the Cat 91 with a full frame, monochrome camera.  But, already, at APS-C, the stars from your Cat 91 look better than the stars from my FSQ-85 with the 1.01x reducer (457mm focal length) at APS-C.  Plus, if you look at images that are taken with the FSQ-85, you will always see the "inverse lighthouse" effect for stars not near the center (caused by aperture vignetting, producing a non-symmetrical aperture function).  Your stars so lar look clean to me.  BlurXTerminator gets rid of most of the "inverse highthouse," but not all.  I guess Mr. Croman did not train his neural net with FSQ-85 images :-).

 

For shorter focal lengths, I have already stopped using the FSQ-85 even with the new (RD-QB) x0.73 reducer from Takahashi, and using the Pleiades 68 in its place.  The Cat 91 may make me mothball the FSQ completely, even though the Baby-Q was my favorite OTA just 6 months ago, after zillions of OTA.  My first telescope was a 5" Newtonian whose mirror I had ground myself back in the mid-1960s when I was in secondary school in Kuala Lumpur.

 

Oh, by the way, you did not mention an electronic focuser.  On my Pleiades 68 and MiniCat 51, I had to mount a ZWO EAF on the fine focuser shaft of the WIFD, otherwise the horrible backlash from the ZWO EAF eats you alive with the "normal" focuser gear ratio of their WIFD.  I suspect I will have to do the same with the Cat 91.  

 

Chen

One of the retailer was selling the very same model of Tak to me...i didn't buy it due to its price. I am glad that Cat 91 is a bigger beast in the room now. Plus WO also looked after me very well, as it is my second tele directly from them.

Edited by SKhan, 18 November 2024 - 01:07 AM.

[SKhan]

Yeah, you are probably getting around 0.5" total (RA + declination) RMS error from that mount, with peak errors of the order of 1" or worse. 

 

I did not try to plate solve your image to see if the elongation is in the RA direction.   If it is, the small motion blur is very likely caused by the mount.

 

Chen

Hey Chen - How to fix this in autoguiding? Do I need to update the guiding settings? Is it a problem with the mount or something which is expected?

[w7ay]

Chen, my son Ren and I will be more than happy to comply. 

Thank you in advance!

 

 

By "shortish" exposures, what do you mean?  30 seconds?  1 minute?  3 minutes? 

The nice thing with a clean star field is that you don't need long exposures to get good SNR.  An exposure like 10 to 30 seconds at HCG gain with an ASI2600MM should be sufficient to get us lots of stars that are not all saturated, and without having to apply dark frames.  It may not be as pretty as an image with a nebula or globular cluster, or galaxy in the frame, but much easier to pixel peep.  I have seen tilt anayzers get fooled when there is something large but bright like M31 or M42 in the plate,  

 

I am definitely curious to see what the true tilt (without using BlurXTerminator) of your copy is, and if your copy of the scope is as good, or perhaps even better than @SKhan's, since that could give us an idea if William Optics is becoming more interested in doing better QC than they have done in the past.

 

If you have time, a fixed exposure value (say, 30 second at 10 dB gain) for each of your L, R, G and B filters would be nice, or if not, just L and B.

 

Other folks may have their preferences and requests.

 

Chen

[w7ay]

Would you be interested in FIT files or JPEG files?  

FITS or 16-bit monochrome TIFF/PNG.  Definitely not JPEG.  

 

And yes, Binx1 please, if you can find some place to host the 125 MB image. Gulp.

 

If not, just small crops for each 4 corners at Binx1, plus some tilt analysis for the full frame.  That should make pixel peepers happy enough, and not need to ship 125 MB around :-).

 

Chen

[w7ay]

Hey Chen - How to fix this in autoguiding? Do I need to update the guiding settings? Is it a problem with the mount or something which is expected?

People who know me from the ZWO forum knows that I no longer comment on ZWO mounts.   You know what our mothers told us -- if you have nothing good to say about something, don't say anything :-).

 

If you are interested in tuning your settings, and since you are using ASIAIR, and assuming that you are using multi-star guiding, make sure that you wait 15 to 30 seconds after changing a setting before deciding if the change was for the better or for the worse.  It takes ASIAIR guiding that long to adapt to changes. 

 

Chen

[w7ay]

WIFD and ZWO EAF

 

One of the problems with the William Optics WIFD is that when you mount a ZWO EAF on it, the EAF protrudes below the dovetail plate of the OTA,  In my case, my OTAs are mounted on a saddle plate that my guide scope is also mounted on, and protrusions below the main OTA's dovetaill plate makes it impossible.

 

This is how I solved it (shown on the Pleiades 68, since I don't have the Cat 91 yet).  First, I have a web machine shop (in Seattle) to machine this plate for me:

 

 

I then drilled and tapped two M3 holes on the ZWO EAF shell to mount on this plate, and bolted the plate onto the WIFD, with a flexible coupler between the fine-focuser shaft of the WIFD and the EAF shaft:

 

 

Nothing protrudes below the plate, and all the openings both reduce the weight and allow easy access to for example the grub screws of the flexible coupler.

 

This is what it looks like from the top:

 

 

I got another plate made in readiness for the Cat 91 :-).

 

BTW, if you are curious, those tube bands are actually ZWO's 90mm camera tripod rings :-).  Can't stand the gaudy colors and weight of the original bands.  When the Cat 91 arrives, I will have to measure the tube diameter and see if I can find a More Blue (Hutech) tube band that fits.  The red bands are even uglier than the blue bands.

 

Chen

Edited by w7ay, 18 November 2024 - 04:20 AM.

[SKhan]

People who know me from the ZWO forum knows that I no longer comment on ZWO mounts.   You know what our mothers told us -- if you have nothing good to say about something, don't say anything :-).

 

If you are interested in tuning your settings, and since you are using ASIAIR, and assuming that you are using multi-star guiding, make sure that you wait 15 to 30 seconds after changing a setting before deciding if the change was for the better or for the worse.  It takes ASIAIR guiding that long to adapt to changes. 

 

Chen

I have shared with ZWO the PHD2 guide log from ASIAir for a resolution. Who knows that it may still end up with you!