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California Extended (Star 71)


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The last couple of nights have been ok in clear sky terms, a bit Moony - but a decent quality sky. So I decided to increase the overall exposure in Ha on this one - I've dropped the 300s subs taken by my little boy (as they were introducing noise) and replaced them with a fair mix of 600 and 900s subs. Total exposure now is just a shade over 6 hours, and its fairly clean as a result.

Ive refrained from going bonkers with the sharpening and contrast - so only one round of each before applying the finishing tweaks. I'll consider colour, but there is hardly any OIII in this so I'm not sure its worth it as Im trying to hoover up other parts of the MW before they vanish for a few months.

 

6h5m (combo of 600s and 900s subs) Ha

Star 71, Atik 383L+, NEQ6

Thanks for looking :)

 

25217204826_66dba772dd_k.jpg

 

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That's lovely. Clean as a whistle.

I did an HaOIIIRGB collaboration with Damian on this a couple of years ago. He donated the OIII. It certainly brought more charm to the HaRGB. I didn't try it in pure NB though.

Olly

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That's nice.  I particularly like the textured effect in the middle which I often find seems to be enhanced in Ha only mono images.  But why does the bright star have some sort of diffraction spikes?

Chris

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1 hour ago, cfpendock said:

That's nice.  I particularly like the textured effect in the middle which I often find seems to be enhanced in Ha only mono images.  But why does the bright star have some sort of diffraction spikes?

Chris

Thats a result of the cell clips, its something you will find in all refractor telescopes (even Taks!) so its nothing to be concerned about. In fact, I usually take it as a sign that the focus was bang-on.

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3 hours ago, ollypenrice said:

That's lovely. Clean as a whistle.

I did an HaOIIIRGB collaboration with Damian on this a couple of years ago. He donated the OIII. It certainly brought more charm to the HaRGB. I didn't try it in pure NB though.

Olly

Cheers Olly! :)

I'll see if I can cobble together a couple of hours worth. But that will be for a standard "red" version - I found the California doesnt really respond well to Cannistra processing when I tried it with the 130pds.

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That's smashing Rob!

I am having flat field issues with my s/h Star 71. It is the slightly older model without the tilt adjuster. However a package from Altair arrived today containing a tilt adjuster so I'm hoping to sort the issue without shipping the 'scope back to the manufacturer (who has kindly offered to adjust it for me).

It's frustrating to waste the clear skies after all that cloud though. I bought the 'frac to avoid the issues around my 150 PDS - but now I have a different set of issues! Arrrggghhhh.... ;)

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2 hours ago, Pompey Monkey said:

That's smashing Rob!

I am having flat field issues with my s/h Star 71. It is the slightly older model without the tilt adjuster. However a package from Altair arrived today containing a tilt adjuster so I'm hoping to sort the issue without shipping the 'scope back to the manufacturer (who has kindly offered to adjust it for me).

It's frustrating to waste the clear skies after all that cloud though. I bought the 'frac to avoid the issues around my 150 PDS - but now I have a different set of issues! Arrrggghhhh.... ;)

Thanks :)

Just be mindful that when adjusting the tilt, only do it in tiny steps becuase its easy correct one corner, only to have another go wrong. Also, I found it difficult to figure out which corner belongs to what corner you are getting on the CCD feedback (as the image is sometimes flipped) - so its probably easier to do it with a DSLR, which is fairly easy to figure out. Messing with small allen keys in the dark is a frustrating experience. Is yours the WO or TS version?

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13 minutes ago, Uranium235 said:

Thanks :)

Just be mindful that when adjusting the tilt, only do it in tiny steps becuase its easy correct one corner, only to have another go wrong. Also, I found it difficult to figure out which corner belongs to what corner you are getting on the CCD feedback (as the image is sometimes flipped) - so its probably easier to do it with a DSLR, which is fairly easy to figure out. Messing with small allen keys in the dark is a frustrating experience. Is yours the WO or TS version?

I've got the WO. I have about a 10 mm gap between the adjuster and filter wheel, and that's only because I have an 8.5 mm spacer in the train from the 150 PDS setup. I cut down two allen keys tonight to get into the tiny gap :) I'm going to have to be very methodical... lol. Ta for the heads up!

It's also very telling (to me at least, as an engineer) that both the newer WOs and the TS version come with a tilt adjuster as standard. 

Did you ever need to adjust either or both of the big brass slotted screws on the top of the OTA to stop play in the draw-tube? These seem to be quite independent from the focus tension allen key grub screw in the focuser. 

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1 hour ago, Pompey Monkey said:

Did you ever need to adjust either or both of the big brass slotted screws on the top of the OTA to stop play in the draw-tube? These seem to be quite independent from the focus tension allen key grub screw in the focuser. 

Yes, tweak those up a little bit to take the slop out of the focuser. Without any adjustment you might notice movement in the drawtube when you hold your camera with one hand and give it a bit of a wiggle (side to side or up/down). Mine has no noticeable wiggle now, whereas before adjustment you could actually hear it.

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