Imaging with the 130pds

[Jonk]

Very interesting info on the 130PDS.

Does anyone have any images taken using the longer 130/900?

We're in the process of butchering one that had a broken focuser, to see what can be achieved using a 450D on a motorised EQ2.

[Thalestris24]

Yes you can attach SW auto focuser, no modification needed

Cheers Martin - I think I'll definitely get one then! I'm still writing the software for my diy usb autofocuser and it deserves something better than the ST-80!

Louise

[tingting44]

Cheers Martin - I think I'll definitely get one then! I'm still writing the software for my diy usb autofocuser and it deserves something better than the ST-80!

Louise

no problem

i love mine, it works fab for me with FWHM too

for the money you can not go wrong

writing software that is past me, fair play!

[Uranium235]

Jonk, on 14 Jan 2015 - 4:16 PM, said:Jonk, on 14 Jan 2015 - 4:16 PM, said:

Very interesting info on the 130PDS.

Does anyone have any images taken using the longer 130/900?

We're in the process of butchering one that had a broken focuser, to see what can be achieved using a 450D on a motorised EQ2.

Im not sure if a DSLR will come to focus on the 130/900, the only images i've found are taken with a modified webcam (google search).... but type "skywatcher 130pds" into google, and you get a torrent of images

[JimFR]

Im not sure if a DSLR will come to focus on the 130/900, the only images i've found are taken with a modified webcam (google search).... but type "skywatcher 130pds" into google, and you get a torrent of images

Barlow required, unless there are mods happening...

Fairly drastic ones!

[Uranium235]

Thanks for confirming that, I thought it might not work.

[JimFR]

Thanks for confirming that, I thought it might not work.

I have been able to take frames with a DSLR this way on a SkyHawk 4.5".

They were rubbish, but it is doable...

[Jonk]

Barlow required, unless there are mods happening...

Fairly drastic ones!

Exactly...The Dremmel has been in action!

It had a broken focuser so that was sacrificed and is now half the height it was.

[Atreta]

Can you tell how you did? i'm considering to have some machine shop to cut a few mm of mine focuser, but i'm yet to decide if it's worth it,

my heart aches with the idea of destroying my little newt

[happy-kat]

Surely it is less destructive to either use a barlow or fit longer bolts to support the primary mirror higher.

[Jonk]

As I said, it had a broken focuser so we chopped half the height off and ground off the plastic teeth (these were mashed). I also removed half of the focuser tube so it didn't protrude into the light path.

The focuser just slides up and down and I've fitted a securing screw to lock it. Not the easiest to focus, but it's only a test really.

A barlow wasn't wanted as it reduces the amount of light and the scope is slow as it is.

We'll be lucky to get more than a minute per sub on it I reckon.

[Chris]

As I said, it had a broken focuser so we chopped half the height off and ground off the plastic teeth (these were mashed). I also removed half of the focuser tube so it didn't protrude into the light path.

The focuser just slides up and down and I've fitted a securing screw to lock it. Not the easiest to focus, but it's only a test really.

A barlow wasn't wanted as it reduces the amount of light and the scope is slow as it is.

We'll be lucky to get more than a minute per sub on it I reckon.

The mount will probably give you a bigger headache, but its fun to try these things, good luck

[poogle]

Wow, some stunning work done with this scope!

I've had the 150p for some time now and recently bought a SXVR-H18 (KAF-8300 chip). After doing some research I thought that binning was out of the question with the 2,97"/pixel resolution (2x2), but seeing Uranium235's images gives me hope

/Patrik

[Uranium235]

2.97" p/p aint bad! I usually reserve binning for mosaics, as it allows me to quickly build something under tricky conditions - albeit at the price of resolution. Think of it this way, its like transforming your 750mm of focal length into 375mm, except without the increase in FOV. Which is only 25mm less than Espirit 80 (2.78" p/p), and 25 more than the Star71 (3.18" p/p)  - but im just comparing resolution here nothing else.

Its probably worth measuring your gain between 1x1 and 2x2 first. Take some flats at 2x2 (using a Ha filter) and achieve a target ADU of something like 24000 - make a note of the time, now switch to 1x1 and see how long it takes to get the same level, then divide one by the other to get your (rough) gain.

[Atreta]

Surely it is less destructive to either use a barlow or fit longer bolts to support the primary mirror higher.

Looks like the 114p is fixed mirror or something, can it still be moved up?

[Atreta]

sorry, this is very offtopic as this is the 130pds imaging topic, please delete my post. i'll make a new one later

thank you

[poogle]

2.97" p/p aint bad! I usually reserve binning for mosaics, as it allows me to quickly build something under tricky conditions - albeit at the price of resolution. Think of it this way, its like transforming your 750mm of focal length into 375mm, except without the increase in FOV. Which is only 25mm less than Espirit 80 (2.78" p/p), and 25 more than the Star71 (3.18" p/p)  - but im just comparing resolution here nothing else.

Its probably worth measuring your gain between 1x1 and 2x2 first. Take some flats at 2x2 (using a Ha filter) and achieve a target ADU of something like 24000 - make a note of the time, now switch to 1x1 and see how long it takes to get the same level, then divide one by the other to get your (rough) gain.

Thanks! What do I do with the measured gain?

Is the gain camera or chip dependent?

[Uranium235]

Thanks! What do I do with the measured gain?

Is the gain camera or chip dependent?

You can use that figure to work out how much time you need for each sub, I find that 600s binned @ f4.4 gives a signal three times cleaner than 600s on my 80ED. So, I can get away with using less - ie: 2 hours binned is normally enough for a clean(ish) pic, and to do it unbinned would take roughly double the time (4 hours).

Im not sure whether the binning gain is chip or camera electronics based (probably both), and will more than likely differ from camera to camera. Thats why you need to check it out for yourself, but theres probably someone better qualified than me to give stats on the internal gubbins of CCD cameras. I just go on real-world observations (which dont always follow whats on paper).

[RogerOfHeaton]

Just to make an introductory post here, I have just "upgraded" from a 10" Dob to the 130 PDS on the EQ6 AZ GT mount. I've a lot to learn but looking forward to much heartache and joy, probably not in equal proportions.

[Thalestris24]

I just joined the club! Have taken delivery of a 130pds  Looking forward to first light - whenever that will be! Have to set it up on the AVX first of course - at least I can do that during the day

[Robp]

Excellent news Thalestris24.

I hope it performs as well for you as it has for me

[Uranium235]

Blimey, got a few people jumping on the bandwagon now

Just be prepared to find a way of balancing out the primary (I used 0.5kg leg weights), these little newts hardly weigh anything so they end up going camera heavy.

[Chris]

I sold one of these little beauties about a year ago and had little luck with imaging ever since! I rejoined the club a couple of weeks ago

[Thalestris24]

Hi Rob

Well I did say a while ago I was thinking of getting one . It's actually not that much smaller than my 150pds - unsurprisingly! I'll probably only be putting a dslr on - plus maybe a filter wheel and definitely the autofocuser, of course. I actually do have some ankle weights though they are 1kg ones. I don't see an easy way of fitting one to the tube except by maybe using tape?

Louise

[Uranium235]

Thalestris24, on 22 Jan 2015 - 1:28 PM, said:

Hi Rob

Well I did say a while ago I was thinking of getting one . It's actually not that much smaller than my 150pds - unsurprisingly! I'll probably only be putting a dslr on - plus maybe a filter wheel and definitely the autofocuser, of course. I actually do have some ankle weights though they are 1kg ones. I don't see an easy way of fitting one to the tube except by maybe using tape?

Louise

My leg weights are held on with a combination of velcro straps (to hold it roughly in place), then backed up with a load of elastic bands to make it a snug fit. That makes it easier to remove if you need to... tape would be a bit of a one-way process (and leaves residue on you nice new shiny OTA if left for too long).