Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

QHY268M & QHY268C Users Thread (Please share your knowledge and tips)


Recommended Posts

5 minutes ago, tomato said:

I was getting warnings in APP that the offset was too low when set at 30, I raised it incrementally until they disappeared. What’s the problem with an offset of 255 apart from losing a little bit of dynamic range?

Well nothing I guess, but that is an issue with APP, I thought it had been sorted a long time ago….

Link to comment
Share on other sites

Thanks for the answers!

I found this excel sheet, it's called 268TradeoffEstimator_b.xls, it shows a lot of stuff that's over my head but looks useful.

image.png.1480a45e90edd85769862eb1d3eaa5d5.png

I think I'll try Mode 1, gain 0, with 300s subs for L and 420s subs for RGB, does that make sense?  Of course if I see a large amount of blown out stars or galaxy core I'll have a play until I get a better result.

I get a decent FW figure from Mode 1 / gain 0 and a similar DR to Mode 0 / gain 26

image.png.4485455507fe4111126da30c1a4188d6.png

Does anything stand out as glaringly wrong with my assumptions?

 

Cheers, Ian

Link to comment
Share on other sites

  • 2 months later...

Just wondering if anyone else sees these specs in their cooler fins, is it dirt or surface mount components ☺️ if it’s dirt should I carefully clean out? Could be something from a nearby conifer. Never noticed them before.

 

AECC8D33-DA4C-4F4E-AD5E-B4D6FE1D0EAF.jpeg

6317D960-F8A5-4F5B-BF17-B616BCEAA49A.jpeg

Edited by Rob_Jn
Link to comment
Share on other sites

  • 7 months later...

Hello QHY268 users…

Hope you had a good Christmas and I wish you a happy new year….

Now to serious business 😂

My last imaging session a couple of weeks ago all was perfect no issues at all, today I put the rig on in my obsy to take flats using my fitted deep sky dad flats panel, and for the first time I have noticed a dark area in the middle of the images at my usual -10, when I warmed the camera, it goes away, so it’s either condensation on the sensor window or frost on the sensor and I think it’s the later, based on the sharpness of the dark area, (closer to sensor sharper the focus), the humidity reading is approx 76% when at zero, so question is this the issue, and why was it fine just 2 weeks ago while imaging…?

Also why would it be frost on the sensor rather than condensation on the inside of the sensor window…?

Thanks all. 👍🏻

Link to comment
Share on other sites

I ran into a similar problem with my ASI533MC a couple of years ago. My cooling tempertaure was always set to -10C and during a particularly cold night over winter, I would get build up of frost on the sensor window. As a workaround, I took a spare dew heater meant for an eyepiece/30mm guide scope and wrapped it around the extension tube in front of the camera. This did the trick and I didn't experience any further frost issues when using that camera.

Fast forward to today where I use the QHY268M, I set the cooling temperature to -5C and I haven't seen any problems with frost build up over winter and/or humid conditions. My dessicant tube is always attached to the camera and NINA shows the internal humidity to be around 65% once it reaches the cooling set point (I could probably do with recharging my dessicant though). So whether it's the reduced cooling temperature or the dessicant tube (or perhaps a combination of the two), this seems to work great for me :)

  • Like 1
Link to comment
Share on other sites

1 hour ago, Richard_ said:

I ran into a similar problem with my ASI533MC a couple of years ago. My cooling tempertaure was always set to -10C and during a particularly cold night over winter, I would get build up of frost on the sensor window. As a workaround, I took a spare dew heater meant for an eyepiece/30mm guide scope and wrapped it around the extension tube in front of the camera. This did the trick and I didn't experience any further frost issues when using that camera.

Fast forward to today where I use the QHY268M, I set the cooling temperature to -5C and I haven't seen any problems with frost build up over winter and/or humid conditions. My dessicant tube is always attached to the camera and NINA shows the internal humidity to be around 65% once it reaches the cooling set point (I could probably do with recharging my dessicant though). So whether it's the reduced cooling temperature or the dessicant tube (or perhaps a combination of the two), this seems to work great for me :)

Thanks.

Just tried it all again this time cooling in stages, when powering this camera on it auto cools to zero, so left it at that for a few mins, then went to -5 for a few mins and then -10 and even -13 and all good no frosting issues….🤔

 

Link to comment
Share on other sites

10 minutes ago, Stuart1971 said:

Thanks.

Just tried it all again this time cooling in stages, when powering this camera on it auto cools to zero, so left it at that for a few mins, then went to -5 for a few mins and then -10 and even -13 and all good no frosting issues….🤔

 

I’ve  had this issue a couple of times whilst trying to take flats on my qhy258m at -15 and the humidity rises above 60% 

It is normally solved by replacing the desiccant and leaving it alone for a couple of days, also I reduce the temperature slowly, and sometimes in stages normally 10-15 min in Nina as I’ve had this problem when I reduce the temp too quickly 

I leave my desiccant tube attached permanently 

Good luck, I’m sure all will be fine 

Bryan 

  • Thanks 1
Link to comment
Share on other sites

Are you meant to have the desiccant tube connected permanently or does it depend on your local conditions?

 I live in very damp Shropshire, my QHY268 cameras stay on the scopes in a Pulsar Dome and at -10 deg C I haven’t seen  a dew or frost problem, so I have never used the desiccant tubes. The humidity value on the mono goes up to around 65% at ambient and drops to around 57% at -10 deg C, that moisture is presumably condensing or freezing out somewhere.

On the other hand, my RC 571 misted up right out of the box, but was fixed by adding a ZWO heater to the mounting plate.

I presume all of these cooled Astro cameras are meant to have a sealed sensor chamber, or else a little tube of desiccant wouldn’t be of much use if they were open to the wider atmosphere? If they are sealed 100% then in theory we shouldn’t have a problem but maybe the seal degrades over time. Didn’t Starlight Xpress or Atik claim to have an argon filled chamber as a USP?

  • Like 1
Link to comment
Share on other sites

15 minutes ago, tomato said:

Are you meant to have the desiccant tube connected permanently or does it depend on your local conditions?

 I live in very damp Shropshire, my QHY268 cameras stay on the scopes in a Pulsar Dome and at -10 deg C I haven’t seen  a dew or frost problem, so I have never used the desiccant tubes. The humidity value on the mono goes up to around 65% at ambient and drops to around 57% at -10 deg C, that moisture is presumably condensing or freezing out somewhere.

On the other hand, my RC 571 misted up right out of the box, but was fixed by adding a ZWO heater to the mounting plate.

I presume all of these cooled Astro cameras are meant to have a sealed sensor chamber, or else a little tube of desiccant wouldn’t be of much use if they were open to the wider atmosphere? If they are sealed 100% then in theory we shouldn’t have a problem but maybe the seal degrades over time. Didn’t Starlight Xpress or Atik claim to have an argon filled chamber as a USP?

Hello,

I don’t think the idea is to leave the desiccant tube on all the time, but just to use when needed for a few days to lower the moisture level.

The chambers are sealed, and like you (I have had my camera about 18 months) and never had an issue until yesterday, my numbers were pretty much the same as yours too, until yesterday, where they shot up and were about 75% at ambient, and 60% at -10, and so cooling as soon as switched on caused the frosting, but when I cooled much more slowly, I got down to -15 with no issues, so for me, although I have no idea why all of a sudden I need to, but it’s time for the first use of the desiccant tube..

SX do fill there sensor chambers with Argon gas, correct, and they will refill them as part of a service too..

Link to comment
Share on other sites

The dessicant tube has been attached to my QHY 268M since new, around three years, I have the camera bolted to the filter wheel so that the dessicant tube is protected by the FW, I was worried about snagging it and snapping the tube off. I use a molecular sieve dessicant and change it twice a year.

My RH is usually 40 - 45%, I measured it before the last change, at the start of the season, and it was 55% at ambient.

  • Like 2
Link to comment
Share on other sites

Another question, my QHY268 no longer cools to zero degrees on connection and power on like it used to, but I have never updated the firmware or the driver in nearly 2 years, I still use an all in one driver from 2022, and USB and firmware from 2021, as shown below, so how has this change happened…? As I see it was changed in newer 2023 driver versions…🤔🤔

IMG_2130.jpeg

Edited by Stuart1971
Link to comment
Share on other sites

1 hour ago, Stuart1971 said:

Another question, my QHY268 no longer cools to zero degrees on connection and power on like it used to, but I have never updated the firmware or the driver in nearly 2 years, I still use an all in one driver from 2022, and USB and firmware from 2021, as shown below, so how has this change happened…? As I see it was changed in newer 2023 driver versions…🤔🤔

IMG_2130.jpeg

I may be wrong but I thought that if you power it up it cools to zero and then when you connect a driver it will idle.  Try powering it on but not starting N.I.N.A, leave it for ten minutes and then connect N.I.N.A and quickly check the temperature then.

Link to comment
Share on other sites

Well, I installed the desiccant tubes a couple of days ago, and I have just fired up the cameras for a possible brief session tonight after what was admittedly probably the wettest day in Shropshire on record, and guess what?

The mono camera now shows 60% humidity at -10 deg C and there is a dark patch in the centre of the image. I think the moral of this story is if it ain't broke don't fix it.

I think the camera starts to cool on start up, but I set it to -10 on start up so I'm not really sure.

QHY268Msettings.jpg.322fdc28e34343ab7cfe720bb7e427cd.jpg

  • Sad 2
Link to comment
Share on other sites

2 hours ago, tomato said:

Well, I installed the desiccant tubes a couple of days ago, and I have just fired up the cameras for a possible brief session tonight after what was admittedly probably the wettest day in Shropshire on record, and guess what?

The mono camera now shows 60% humidity at -10 deg C and there is a dark patch in the centre of the image. I think the moral of this story is if it ain't broke don't fix it.

I think the camera starts to cool on start up, but I set it to -10 on start up so I'm not really sure.

QHY268Msettings.jpg.322fdc28e34343ab7cfe720bb7e427cd.jpg

This is what I suffered with out of the blue, dark patch in the middle, but since then I have cooled the camera to -10 more slowly (over 10 min period) and it’s not been an issue, but I too fitted the desiccant tube yesterday, to my QHY268m for the first time since it was purchased new…😮😮

Edited by Stuart1971
Link to comment
Share on other sites

4 hours ago, tomato said:

Well, I installed the desiccant tubes a couple of days ago, and I have just fired up the cameras for a possible brief session tonight after what was admittedly probably the wettest day in Shropshire on record, and guess what?

The mono camera now shows 60% humidity at -10 deg C and there is a dark patch in the centre of the image. I think the moral of this story is if it ain't broke don't fix it.

I think the camera starts to cool on start up, but I set it to -10 on start up so I'm not really sure.

QHY268Msettings.jpg.322fdc28e34343ab7cfe720bb7e427cd.jpg

Oh that sucks, especially as it was fine before. 

From what I've read online, I don't believe these QHY268M cameras are argon sealed by the manufacturer. I did see some other users backfilling the chamber with argon (per cloudy nights below), but I've never tried this so I couldn't comment on whether this is typically how a manufacturer would do it or not. 

https://www.cloudynights.com/topic/805027-qhy-268-chip-chamber-window-fogging-and-humidity-measurements/

Link to comment
Share on other sites

Maybe the act of installing the tube introduced some moist air into the chamber,  which the desiccant will need time to remove. In hindsight I should have run the dehumidifier in the dome and got the humidity level inside to a minimum before fitting the tube, oh well.

Link to comment
Share on other sites

20 minutes ago, tomato said:

Maybe the act of installing the tube introduced some moist air into the chamber,  which the desiccant will need time to remove. In hindsight I should have run the dehumidifier in the dome and got the humidity level inside to a minimum before fitting the tube, oh well.

Hmm, I did bring my camera into the house to fit the desiccant tube as I was swapping my filters out for some new 3nm ones too, and humidity was much lower inside, I also took the screw out of the camera and immediately put the tube in, to avoid much air entering, so hopefully it won’t get worse beofre it gets better, will have a look later and see as it’s been 2 days…

Link to comment
Share on other sites

23 minutes ago, tomato said:

Maybe the act of installing the tube introduced some moist air into the chamber,  which the desiccant will need time to remove. In hindsight I should have run the dehumidifier in the dome and got the humidity level inside to a minimum before fitting the tube, oh well.

Can I ask why you use an offset of 255, which is the max, this is way way too high, you only need 25 or 30, also the high gain mode 1 is the best mode with an offset of 30, and gain of 56, seems to give the best results

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.