Planning of a Cepheus mosaic - Forums

Topic starter

Sep 17, 2017

Hi guys!
I am planning a mosaic of the cepheus constellation with all of its interesing objects. Please take a look here.
What do you think? Polaris is pretty near, so the frames will be heavily rotated next to each other. Thus, I need more overlap. Would you prefer 4 images in a row? Anything interesting that I miss with this planning? Do you think that 30 minutes (60x30s) per tile at ISO1600 and f/2 will be sufficient?
By the way, is there a free software for planning such mosaics?
Setup will be a Star Adventurer, Sony A6000, Samyang 135mm f/2

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Charles Harris

Sep 17, 2017

Hello,
I can't provide any technical advice, but just wanted to comment: From the looks of your work, I would expect this venture to result in an original looking, very artistic production. I have just taken notice to the Cephius region and attempted some photos myself, thanks to finally modifying my ShyShed dome to access the northern sky. Good luck. I will be following: Your work is quite beautiful..
Charles

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Björn Hoffmann

Topic starter

Sep 17, 2017 · Edited: Sep 17, 2017

Hi Marcus,
thanks for your input! The problem I see with Cepheus in constrast to your (and also my) mosaic of Cygnus is, that Cepheus has much more faint structures and is not that bright anymore. I would love to see all those molecular clouds and dark nebulae. However, it is still a pretty star-rich region. I think I should plan the first night only for experiments, before I capture the complete mosaic. Last year I visited Cepheus one time: http://www.astrobin.com/261491/.
Even though I have good flat fields for the Samyang, f/2 is really bad for the edges. I guess you are right and I have to increase the overlap. Then 3x3 won't be enough anymore and I need to switch to 4x4. I will try it.
Another enthusiastic idea would be to extend far to the left to include Cassiopeia.

But I guess the weather won't allow such a project..

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Björn Hoffmann

Topic starter

Sep 17, 2017

Another problem which just came up: The six very bright stars should always ideally be located near the center of the frames. Otherwise, the Samyang will create those ugly flare disks around them. But maybe that's just a minor problem..

Björn Hoffmann

Topic starter

Sep 22, 2017

Update! Last night I took the first seven tiles. It will take a whole winter night to take the complete mosaic in one run. I messed up the settings and used iso 800 instead of 1600 due to initially bright sky. I will process it this weekend. Let's hope for the best!

Björn Hoffmann

Topic starter

Sep 26, 2017

Björn Hoffmann:
By the way, is there a free software for planning such mosaics?Setup will be a Star Adventurer, Sony A6000, Samyang 135mm f/2
Mine ... but it is full of little bugs since I am lazy and didn't plan to distribute it. I wrote it just as a help for my pro data mosaics.

Give me your setup data (sensor size, pixel size, FL, position angle) and I'll give you back the centers!

Cheers

Hi Roberto! Thanks for your help, but I am using a Star Adventurer, so centers won't help me. What I am searching for, is a program that automatically generates the mosaic tiles with a fixed overlap. I created mine manually in Powerpoint, which was time comsuming and not very precise.. It still worked, but there must be a better solution.

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Björn Hoffmann

Topic starter

Sep 26, 2017

I am using bright stars in the single tiles to orientate myself by using the liveview of my camera. It worked quite well with my handmade mosaic plan that I showed in the first post. Once I have found the correct orientation for the first tile in a row, it is easy to move to the next one.