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Wieben

Skywatcher Quattro 10CF first light

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Hello,

This is my first post in this forum.

While awaiting the delivery of my own Quattro, I have been following the discussions of the telescope closely here in other threads, and want to give some thing back to the forum.

Here is my first light test of the Quattro.

Since this is a fast telescope I was excited to see if my current coma correctors would do the job. I have the Baader MPCC and the Skywatcher coma corrector.

After collimating the telescope I made some test shots on the double cluster in Casiopeia swapping between the two coma correctors. The camera is a stock Nikon D700.

Both coma correctors are performing reasonably well, but it turns out the Skywatcher corrector is acting as a 0.9 reducer giving resulting in a fast f3.6 system. This was found plate solving the images. The nice effect of this is an even wider FOV and a very fast system. The down side is slightly worse coma and a bit more vignetting, which is expected due to the shorter focal length.

Here is the comparison made in CCD Inspector.

Quattro%20coma%20corrector%20Baader%20MPCC%20vs.%20SW%20coma%20corrector.jpg

The collimation and centering of the optical chain is not perfect, but not that far off. Below is the analysis of the flat frame using the Skywacther coma corrector.

Flat%20CCD%20inspector.jpg

The optical center is not far from the physical center.

This is a full frame sensor. 1/3 of the light is lost 2/3 away from the center.

I decided to use the Skywatcher for the real first light test.

All shots were done using a Nikon D700, EQ6Pro and guided with PHD guiding with the Orion SSAG. Darks, flats and bias used for all pictures. Stacked in DeepSky Stacker using the median method. Processed in PS CS5.

The location was a fairly dark spot at my parents summerhouse in Denmark.

Here is a 30 second unguided shot from the porch. (Nikon lens @20mm).

M%C3%A6lkevej.jpg

The temperature was between 14-12 degrees C and the humidity was very high. I need to get some anti dew installed for the large secondary asap.

First object was good old M31.

I got 3 hours of 10 subs, and a hand full of 3 and 1 minutes subs for the core details. All ISO800.

M31.jpg

Next object was M45. 1 hour 40 minutes using 10 minutes subs ISO800.

M45%20Thur%C3%B8%20Quattro%20SW%20indoor%20flats%20100min%20working.jpg

The final test object was NGC7000. My camera is not modded, but the fast f3.6 is helping to get a bit of red after all.

NGC7000 90 minutes in total using 10 minutes subs ISO800.

NGC7000%201st.jpg

I am very happy with the telescope and the first light. Next time i will test the Baader MPCC. I haven't decided the next object yet, but I would love to get some good data on M78 when Orion rises a bit higher.

Thanks for watching.

Best regards,

Heine Wieben

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What a first post. Most of that flew higher above my head than the DSOs themselves! Fortunately for me, the images speak volumes, and M45 in particular is spectacular for any length of exposure time. The fact it was only 100 minutes makes it simply remarkable.

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Looks like you're getting some lovely shots . I particularly like the one of M31. All with an unmodded Nikon - excellent.

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Very impressive. You've got the Quattro working to specification, I think. Very strong signal in fairly short exposures and fine images as a result.

Olly

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I was just contemplating either the 8" or 10" CF Quatro as my next scope... that's kinda decided it for me.... those are lovely images :-)

Ben

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Looks like a reasonable scope- do you think good colimation will be ultra critical on such a short focal ratio tube?

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Looks like a reasonable scope- do you think good colimation will be ultra critical on such a short focal ratio tube?

That's exactly what I just started another thread about :-)

I don't have any clever computer means of checking colimation and have never actually colimated anything before... I was wondering if this was going to be a total nightmare? :-)

Possibly a price worth paying for a megga-fast 1m fl scope?

Ben

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Thank you for your kind comments.

Regarding collimation: Collimation will be critical on a fast newton, but this is not a difficult thing to get right.

I'm only using a cheshire to collimate. I use CCD inspector (can be tested for free on a 30 day trial) to validate my results. CCD inspector can also be used for live collimation, but I haven't tried that yet.

Start by squaring the focuser, center the secondary in the sight tube, tilt the secondary to aim at the circle on the primary, adjust the primary to center the dot in the circle - use the scope :-)

When the collimation is done right you unly need to check and maybe once in a while adjust the primary a bit. The Skywatcher mirror cell is great and I rarely have to re-adjust the primary even though I transport the scope 1 hour back and forth on every session.

I think the whole fear of newtons and the need for collimation is highly exaggerated.

I mainly see the collimation as an advantage, as you can always adjust your scope to make it perform as good as possible. The scope will not suffer form pinched optics, and you don't need to send it to the manufacturer or experts if the scope needs adjustments.

Once learned (either by trial and error or from an experienced fellow astronomer), collimation is not a hard thing to get right. To me the greatest disadvantage of a newton is problems with dew. It's probably a bit easier to put a heating strip on a lens than on a mirror - but this is a minor thing. I love the aperture/price performance of a newton telescope. For me lenses is mainly used for guidescopes ;-)

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Great post Heine, and a big welcome to SGL!

I have the same tube as you (10" CF) and am very impressed with it so far, although I have only used it for 10 or so hours.

I am very interested to see that the Skywatcher CC reduces the tube by 0.9. Given that I use a small chip mostly with mine that makes a very tempting combination. Are you absolutely sure of that effect?

I am looking forward to more of your pictures. The Nikon seems to have performed exceptionally well, lovely star colour throughout.

Thanks

Tim

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I am very interested to see that the Skywatcher CC reduces the tube by 0.9.

Thanks

Tim

Yeah, I found that interesting too, since that is the CC I have as well. I haven't measured it any way, but would it have the same effect on the 8" Quattro I own as well?

Oh, and almost forgot, great images too! :rolleyes:

Edited by Black Knight

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Those Boren-Simon GSO variants have been available for a little while separately, they are an f4 scope natively but the reducer takes it way down to f2.8. I was considering getting one at one point, but apparently when you get much faster than f4 then narrowband filters stop responding as expected.

But f3.6 sounds very tempting........

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Thanks for the new comments. Highly appreciated.

Tim and Andy: Regarding the 0.9 reduction. Yes I am sure. The reduction is expected to be seen with the 8 inch'er as well.

To validate the reduction factor I found my latest picture shot with my old scope (SW Explorer 254 soon to be for sale if anybody is interested) where I used the SW CC as well. Maxim again gave me the same result with a 0.9 reduction.

It was a shot of the Cocoon which I think came out very good (link to the processed picture (Explorer 254 SW CC)http://dl.dropbox.com/u/13559902/cocoon%2095%25%20stars%201st.jpg

I want to add an extra picture from the first light with the Quattro.

Due to very high humidity I only managed to get 90 minutes of the Veil before the optics drowned in water.

Again 10 minutes subs ISO800.

Veil%2090%20min%20Quattro%20SW.jpg

Btw. I spoke with my friend at the local astro shop. He was surprised of the reduction of the CC and spoke to Skywatcher. They say the CC is not made for the Quattro, and that they are working on releasing a coma corrector specifically made for the Quattro - very interesting indeed. Not that the current CC is bad - it seems to work OK, but smaller stars and absolutely zero coma is always welcome.

Edited by Wieben
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Btw. I spoke with my friend at the local astro shop. He was surprised of the reduction of the CC and spoke to Skywatcher. They say the CC is not made for the Quattro, and that they are working on releasing a coma corrector specifically made for the Quattro - very interesting indeed. Not that the current CC is bad - it seems to work OK, but smaller stars and absolutely zero coma is always welcome.

TBH, I have wondererd about the suitability of the Skywatcher CC and the Quattro. But OVL (Skywatchers UK distributor) advertise the Skywatcher CC as "Optimised for Sky-Watcher fast-ratio f/4-f/5 Newtonian Reflectors/Dobsonians". Not on their website, but in their print adverts. In any case, I already had my CC from my old Explorer 200P, so no big deal really.

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Very interesting Heine, thank you!

I think I might order a Skywatcher CC if it definitely reduces. Your Veil picture is beautiful, is that with the Nikon too? Some of those wisps are extremely feint and dont even respond well to a dedicated CCD camera (I was just processing a pic of the same area) but the Quattro+Nikon has come up trumps there for you!

Tim

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Crikey Nikon D700!

I just ran the NGC7000 through Pixinsight DBE tool and curved it a little..

Hope you dont mind this was just to see the separation of the wall with the rest of the nebulosity...

Respect to the Nikon d700.. ;)

And the user :o

Wonderful image set..:rolleyes:

post-15416-133877676187_thumb.jpg

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Thanks Tim and Coco,

Andy, I guess the SW CC is just as the Baader MPCC. Sweet spot f4.5-5 but works between f4 and f6. I got no complaints on the performance. Next time out I will do some long exposures with the Baader. Previously the Baader gave me lots of reflections when shooting bright stars. The SW CC was better in that respect.

Tim and Coco, yes the Nikon D700 performs great. I think this is due to the large pixels. I'd love to see how a modded D700 would work.

Coco, of course it's ok to play with the data. You managed to get good contrast there.

Br

Heine

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Super images, you have got the scope set up very well.

I have the same scope but using a smaller sensor than the DSLR. Getting some significant vignetting due to the filters (thinking of upgrading to 2inch ones - Expensive !:rolleyes:).

Cheers

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