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Hello All, This thread is to discuss everything Hyperstar with the edge HD. I have had experience imaging on the Edge HD 8" with a QHY10. I'm glad to help anyone imaging with hyperstar if I can. Clear Skies, Scott |
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Thanks Scott, When the time come to upgrade to the HyperStar. I will be looking for you. But it will be for a while tho because I'm new and been spending a lil bit too much lately on hardware and software. So it's a pleasure knowing someone with the HyperSkillz 8) Thank You Orlando |
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Same for me, I have found a decent set of options that work pretty well on it. However a lot of times you can get better results with a short refractor. It is certainly a more expensive route, even if you already own an EdgeHD. However it is hard to beat 8 inches of aperture.  |
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| I have an EdgeHD-11 with Hyperstar and the QHY10. Love the combination. Also getting ready to purchase a WO 102 refractor as a portable scope. The image size and scale (with the FR) is almost exactly like the Hyperstar on the Edge. I'm really itching to make some comparison shots. |
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| Are there any recommendations on taking flats? I shoot with a canon 50D and typically the flats remove the vignetting, but after doing DBE in PixInsight, there tends to be this rectangular halo/donut that runs a bit inside the edge of the picture. Not sure if there is anything specific with the exposure for the flats, but I mostly just aim at getting the histogram clear from clipping at the low and high ends. |
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I normally set Canon on AV mode and make sure you using the same ISO as your Lights. I'm using BackyardEOS "BYE". I also notice that if you take a lot of BIAS and FLATS it will make you processing cleaner in Pixinsight "PI". I would also start a new thread on DSLR in our channel because this channel is intended for HyperStar equipment. Hope I was able to help you Thank You Orlando |
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Here's one place to start: http://www.cloudynights.com/page/articles/cat/articles/the-amazing-hyperstar-a-guide-to-optimize-perf-r3013 John |
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Orlando DeJesus: Thanks Orlando. Posted here because the question was specific for the EdgeHD with Hyperstar. Haven't experienced that issue on the EdgeHD at prime focal length or with a FR so was assuming there was some specific trick with taking flats due to the Hyperstar. Wanted to see if any other users experienced a similar issue or if I am just an odd duck. I'll post up an update if I pinpoint the issue. John Hayes: Very informative. Thanks John! I've read about that elliptical mask trick and am planning on trying it out next time I image. -Chris |
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| Hyperstar is great but not as easy as people try to sell it. It takes quite a lot of time to get the system working well. I am hopefully on the final stages to achieve this. |
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| I never bother with flats. However, I only do narrowband with it and my imaging camera has a very small chip so I don't hit vignetting issues. |
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| Yes. Using a DSLR camera with Hyperstar tends to create the 'odd rectangular' ghost shadow. I've not had any luck removing it with flats, but the mask sounds encouraging. Since I've moved on to the QHY10 (cylindrical shape) the issue has gone away. |
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Michael J. Mangieri: Michael J. Mangieri: Thanks Michael. That's good to know because I was going to get the hyperstar first and use it with my canon. So basically I need to upgrade my camera and then get the hyperstar ;) |
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Orlando DeJesus: I agree. I suggest getting comfortable with CCD imaging before jumping into hyperstar. |
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Michael J. Mangieri: I might have a solution for the odd rectangular shadows created by DSLRs. I recently removed the mirror from a t2i and the shadow/artifact vanished from my images. I also removed the LPF-2 filter from the camera as well as added an IDAS LPS-D1 to my image train so those might have also helped with the fix. However, Comparing the vignetting in the flat frames to the location/shape of the "odd rectangular shadow", I have a very good feeling that the vignetting from the mirror is the main culprit to the rectangular shadow/artifact. I have a comparison shot showing this shadow gone, so I'll upload it sometime this week and post to the thread. |
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If you review my Hyperstar guide (link already posted,) you will see that the rectangular shadow is caused by DSLR mirror box vignetting of the fast off-axis rays. Good flats will allow it to be calibrated out. John |
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John, The "ghost shadow" artifact I am referring to is something that becomes visible after flat frame calibrating the image. Experimenting with various exposure settings for the flats would not remove this. Refer to the link below, as I had time this week to do a quick comparison between my mirrorless T2i and my unmodded 50D. If you look through the revisions, you can see that this artifact is in the same location as the vignetting of the mirror box for the flat frame. With my mirrorless T2i it is no longer present. Additional clarification/info is typed out in the "Description" section.  |
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In principle, if the shadow from the mirror is due to vignetting, it will calibrate out. The problem with any DSLR is that the "shadow pattern" may not all be strictly due to light being blocked. In your case, the rear of the mirror mount may be smooth enough to be reflecting stray light onto the sensor. When that happens, the stray is additive (i.e. not multiplicative,) which means that it will not perfectly divide out during flat calibration. The fast speed of the HyperStar makes strays within the camera mirror-box much more likely. In your mirrorless camera, the distance to the sensor is less and it probably has better light baffling, which is why you don't see the same thing. With a stray reflection, the other problem is that the strength of the stray is often source dependent so it may vary between objects--or even where you have the scope pointed in the sky. The way to test that theory is to apply thin black flocking to the back of the mirror mount. If you get it right, I predict that the artifact that you are seeing should disappear when you calibrate. John |
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| Thanks for the explanation regarding the stray light, I didn't even consider that. I might try to test out that theory when weather clears up again. |
