9 replies to this topic

[sdeming]

Hello my Friends!

 

Last night I went after the Christmas Tree Cluster. I got an early start (I travel to my site) and was up and imaging by 7:30. I planned to get five hours of exposure time in, but within a few minutes that changed. My camera is a QHY294C. Initially, I was using a 2 minute exposure for my lights, but within two or three captures in live stack it started dropping frames. I tried and tried but couldn't figure out what was happening. I shut everything down, rebooted and SharpCap would capture two frames, then drop everything after that. I changed my exposure time to 90 seconds and things seemed fine, until frame 73, then it started dropping frames again. I had this issue with the ZWO294pro, but never with this camera. I changed the USB traffic, checked for wrapped cables, I could not for the life of me figure out what was going on. This morning I sent an email to QHY customer support to see if they have any answers. The other issue I'm having with this camera is capturing flats and dark flats. The histogram won't stay still and the exposures are all over the place. Is this typical for short exposures?

 

Below is the processed image.

73 lights

40 darks

40 flats

40 dark flats

 

Thank you!

 

Scott

 

Attached Thumbnails

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Edited by sdeming, 19 January 2021 - 05:46 PM.

[jim kuhns]

Scott thanks for posting. You still have 73 lights to take off your
Christmas tree?

[GR-Amateur]

Framing. You missed the cone...
One usual problem that might be an issue here is the USB port of the laptop, if that’s your setup. Two adjacent USB ports (side by side) most of the time is actually one port splitted into two via an internal hub. Having those two USB ports in use, especially with a camera included, you might compromise data transfer stability or create other kind of conflicts.

[sdeming]

Framing. You missed the cone...
One usual problem that might be an issue here is the USB port of the laptop, if that’s your setup. Two adjacent USB ports (side by side) most of the time is actually one port splitted into two via an internal hub. Having those two USB ports in use, especially with a camera included, you might compromise data transfer stability or create other kind of conflicts.

Hello and thank you for your feedback. Framing - yes, I knew I didn't have the cone in the frame, but I also knew I was going to do a meridian flip and have to plate solve to center, so I wasn't sure I could get centered again by maneuvering the hand controls. I'm fairly new at this. However, I think I'm going after this target again on the next clear, moonless night and definitely centering the cone.

 

As for the USB, I forgot about the splitting of ports when they're next to each other. I've had similar issues running hardware on my desktop. Question - I've read that you should always run the camera USB directly to your laptop. Here's my setup. I have a powered USB 3.0 hub that I connect my guide camera and hand control/mount to. A cable runs from the hub to my laptop. I then run the camera cable directly to my laptop. And you are correct, the two USB ports are side by side. Should I run the camera cable through the hub? Would I risk losing data transfer doing that? I'm all ears!

[GR-Amateur]

That depends on the number of ports that you have available (or maybe a thunderbolt port which although I was scared of, due to its high amperage, I recently discovered that works like a charm).

The governing rule when it comes to USB ports is to always use the same port for a certain gear while port’s address or dedicated drivers might create discrepancies with the operating system and/or negotiating software.
In general try and error is the only way to go. Communication of main imaging camera is not constant but when it sends data sends big chunks of bytes, guiding camera on the other hand is almost continuously sending smaller datapackages. The communication of the mount is not so heavy but is little bit more sensitive when it comes to stability while probably uses little bit more generic data and negotiation approach.

If you don’t have enough ports and nothing else works, then maybe someone that have experienced this problem might fill in (probably the only way around it would be some other special hub or gadget). Many fellows here are successfully packing their laptops with cameras, filter wheels, focusers, automatic beer openers... you name it

[sdeming]

That depends on the number of ports that you have available (or maybe a thunderbolt port which although I was scared of, due to its high amperage, I recently discovered that works like a charm).

The governing rule when it comes to USB ports is to always use the same port for a certain gear while port’s address or dedicated drivers might create discrepancies with the operating system and/or negotiating software.
In general try and error is the only way to go. Communication of main imaging camera is not constant but when it sends data sends big chunks of bytes, guiding camera on the other hand is almost continuously sending smaller datapackages. The communication of the mount is not so heavy but is little bit more sensitive when it comes to stability while probably uses little bit more generic data and negotiation approach.

If you don’t have enough ports and nothing else works, then maybe someone that have experienced this problem might fill in (probably the only way around it would be some other special hub or gadget). Many fellows here are successfully packing their laptops with cameras, filter wheels, focusers, automatic beer openers... you name it

This is the hub I'm currently using. It states pretty high transfer speed.

 

https://www.amazon.c...0?ie=UTF8&psc=1

[GR-Amateur]

Is better to have direct connection without hubs if this is not possible due to port availability then try and error or some other gadget even Astro dedicated. Astro cameras don’t like hubs

[sdeming]

I just posted this on another thread dedicated to cables and ports.

 

I went out two nights ago for some testing and tuning. I ran the original cable that came with the camera to a USB powered hub. I then ran this cable https://www.amazon.c...0?ie=UTF8&psc=1 from the hub to my laptop. Everything worked perfectly!

 

Thank you ALL for your input. I greatly appreciate it!

 

Scott

[Madratter]

I'm also working on this target and intentionally framed as you have with the cone nebula out of the frame. I wanted to emphasize the reflection nebula. It is a valid artistic choice.

 

This target is relatively hard for a number of reasons. So hats off for going after it.

[Aquat0ne]

Looks great.

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