We have an AC455M - AFW - SC4 - AOX combination. The Camera and filter wheel appear to be working quite well, especially after the cooler upgrade. However, I tried setting up the StarChaser, and I don't seem to be able to get it to focus. I've adjusted the focus the full range, and all I see are a few fuzzy donuts in my FOV over the full range of the focus. And, for some reason, after I tried the focus process, I'm now having trouble getting the SC4 camera to show up in Maxim DL, despite power cycling the AC455 and SC4, rebooting the computer, etc. In order to connect the AC455 I had to turn the AOX off in Maxim so that Maxim doesn't look for the SC4 camera. Our mount does a good job tracking for 120 sec exposures - larger than that we start to get star tracks. Any suggestions? Thanks!
Hi Bill. Let's try to break this down into pieces, otherwise it will be a bit of muddle trying to sort it out. A) Software and hardware setup to make sure both cameras are seen. B) Optical setup to fix the focus. A) Software and Hardware 1. MaxIm settings. Quit all programs. Please send over your MaxIm settings folder. Zip up the folder Documents\MaxIm DL 7 Use [Upload a File] to attach it here. Then we can have a look at how you have things configured on your system. 2. Version 7.2.2 Verify you have MaxIm 7.2.2 Help... About will show you. Help... Check for Updates will take you to the page to download the latest. Quit. 3. Device Manager Power on the SC-4. Start the Device Manager Under Universal Serial Bus, you should see SBIG Camera A SBIG Camera B These are two parts that make up the StarChaser. Like this: If you see that, then Windows is talking to the StarChaser. Move on to the next section. #4. If you don't see that, look for an Unknown Device, or a device in an error state with a yellow exclamation point like /!\ If you see that, either the cable is bad, or if you are using a hub or extender, try connecting the StarChaser directly to back of the computer with a known-good short cable. If you see something else, let me know and we'll figure it out. A screen shot would help. 4. Start the DL Config x64 program Help... About The DLAPI.dll should be 4.1.2.5 It will show a list of files, similar to this: Code: dlapi.dll ......................... 4.1.2.5 DLAPIWrapper.dll .................. 4.0.2.0 ASCOM.DLImaging.Camera.dll ........ 6.4.26.0 ASCOM.DLImaging.CameraExt.dll ..... 6.4.26.0 ASCOM.DLImaging.FilterWheel.dll ... 6.4.26.0 ftd2xx.dll ........................ 3.2.16.1 ftd3xx.dll ........................ 1.3.0.10 [Copy to Clipboard] Paste in your reply. 5. DL Config x64 should list both devices. Check that it shows the SC-4 under the USB devices, and the AC455 under the network/Wi-Fi devices. Quit. 6. Launch MaxIm DL Pro. Camera Control - Setup tab Camera 1 [Setup] Setup DL Imaging Camera Model = DL Imaging Make sure AO is off. AO has to be associated with Camera 2, the SC-4, on Sensor 1. [Advanced...] In the list, you should see the AC455xxxxx and the SC1300xxxxxx Make sure [x] Auto Scan Network is on so that it can find the AC455. Double click on the AC455, so that it becomes the active camera. [Close] [OK] Camera 2 [Setup] Setup DL Imaging Camera Model = DL Imaging If you want to use AO, set it to Sensor 1 (the first sensor on Camera 2, the guider). AO has to be associated with Camera 2, the SC-4, on Sensor 1. Or leave it off until we sort this out. [Advanced...] In the list, you should see the SC1300xxxxxx (and possibly the AC455, depending on network scan). Double click on the SC, so that it becomes the active camera for guiding as Camera 2. [Close] [OK] [Connect] Both cameras should work. If you have issues, let me know what you run into. Screen shots and log files help. B) Optics You'll have to remind me what you have. a) What is your optical setup? e.g. scope optical parameters eg aperture, focal length or f/ratio b) Do you have a focal reducer/field flattenner ? c) What is the focuser/rotator, and what diameter is the draw tube (3 inch inner diameter? 2 inch?) You may want to pull the instrument package out of the focuser draw tube, and do this next part on the workbench/kitchen table. Set the filter wheel to a clear slot. Look down the nose of the camera package. Check that you have assembled the SC-4 onto the filter wheel in an orientation that means the pick-off mirror is on the "long side" of the AC455 sensor. Adjust the SC pick-off mirror position so that it is as far in toward the main image sensor as possible, without causing a shadow on the main sensor. You'll want to check this again once on the telescope. Like this: Green arrow pointing at the front edge of the pick off mirror. Red rectangle is the AC455 image sensor. Blue arrow shows the front edge needs to move to the edge of the AC455 image sensor, but not overshadow it. Let me know how it goes.
Colin: This is to answer Part B - a,b,c We have a pre-widefield 2011 PlaneWave CDK-17, with an IRF-90 Focuser/Rotator. The CDK-17 is Focal Length = 2939mm Aperture = 432mm f/6.8 We don't have a focal reducer or field flattener. Then, in order to achieve proper back focus, we have the configuration of adapters shown in the attached image connected between the focuser and the camera. All the openings are 3". The 600327/600328/200377/200377 combination adds 1.5” to the back focus. This combination achieves focus near the middle of the focuser’s range. (22278 microns out of 40000 microns). We do have the pick-off mirror oriented on the "long side" of the AC455 sensor. When I was attempting to focus, I was getting star images (very out of focus - fuzzy donuts), but turning the focus knob didn't seem to bring them any more into focus. (How many turns does the focuser knob have over the full range? I was a little hesitant to try to turn it too hard!) I didn't take the unit off the focuser yet, but I'm pretty sure the pickoff is not shadowing the sensor.
My colleague @Doug may be able to provide guidance - eg # focus turns. There's two "variables" you have to work with. Position of pick off mirror, position of sensor relative to the pick off mirror. Here's a sketch of what goes on inside the SC: Blue arrow is the distance through the filter wheel, filters, optical chamber window, to the image sensor. I'm assuming you've focused the IRF90 to give tack sharp stars on the main sensor. Variable 1: pick off mirror position (POMP) : can be slid in/out toward the centre of the optical axis, by unlocking and sliding the assembly. (Right black arrows). Variable2 : sensor position (SP) - the focal reducer lens and image sensor move on a threaded shaft. (Left black arrows - I should ahve used a different color). Since adjusting the SP isn't getting you quite to focus, adjust the POMP. You might have to move it in toward the centre of the optic axis (more to the right in the diagram) to shrink those donuts as tight as possible. Then use the SP knob to fine-tune focus. The SC stars will have coma due to the 90 degree change in light path (green arrow), so they won't be perfectly round, but should not be donuts. The orange lines represent the light cone through the IRF90. Moving the POMP so the edge of the mirror doesn't shadow the main sensor and stays inside the orange light cone is key. Other thing pro tip: Use a "clear" filter, instead of an empty slot. That way the refractive index will be the same as the filters you will be using. Otherwise the focus can be out by perhaps 1 mm for 3mm thick filters.
Adjusting the POMP seems like the way to go. I’ll give it a try! We’ve done a V-plot autofocus to find the optimal focus for AC455. And we are doing this with the luminance filter - all our filters are Astrodon 3 mm - parfocal. Thanks!
Depending on the equipment used, the focus may not be within range at all possible pickoff mirror positions. Moving the mirror will likely resolve the issue. Each full turn of the focus knob moves the sensor (and focal reducer lens) by 0.1" / 2.5 mm. It uses left-hand thread so that the motion is intuitive, i.e. turning clockwise moves the focus in. This way it works the same as a telescope focus knob. (It does indicate the direction on the front of the knob itself.)
