RolandKol

28 minutes ago, dph1nm said:

I guess one issue will be what happens if you have a bright source in the image which gives too many photons to count one by one!

NigelM

If QIS will not be able to perform as SPAD from the The example with the lamp above, - I will be waiting for SPAD
Interesting, how they will react on the light pollution 

I have a very slight hope Astrodons will become dinosaurs once these sensors will hit the market 

And did I understand it correctly,

35mm extension tube is needed for DSLR even if FF is used?

Thanks for a nice review.

As per balance and the locking screw,  - how stiff is the drawtube without locking? And won't you lose camera at some point?

Why not to turn OTA in the rings 180 degrees?

There are 2 types which are mainly  used, - Skywatcher Coma Corrector (which is also 0.9 reducer) and Baader MPPC  (no reduction)

Not sure which is a better one.

There are some more, but usually more expensive.

 nice

as per ASI1600MM, - it is probably the cheapest cam with quite a large sensor to give you a nice FOV, but there are alternatives like Altair Astro Hypercam 1600 which has even 4GB DDR3 RAM (not sure if it does any difference, for me even 256MB is enough).

Also, there are some "quite cheap" CCD cams with smaller FOV.

You probably know this web http://astronomy.tools/calculators/field_of_view/ , but check what you would like to have at the final image before you pull the trigger!

P.S.

Also, always keep an eye on the backfocus of the camera you choose. For example ASI1600 backfocus is only 6.5mm which allows to use small 31mm Filters without vignetting. The larger the backfocus of the camera the larger vignetting you will get with small filters... And if you will be made to go for a larger filters, - like 36mm, - check their prices first 

1 hour ago, Andywilliams said:

• Hi all,

Having read a fair bit of this thread and also being impressed by the quality of the images, I am very tempted to buy a 130 PDS and give it a crack !

A couple of questions though and I apologise in advance if these have already been asked ad nauseam.

I have enough money to invest in a HEQ5 pro. I also have enough to put my first steps into mono ccd imaging.

I don't have enough left over for the recommended 80mm esprit, so I thought I might have a go with this impressive scope.

1) I will need to saw off the focussing tube from the get go ? I find this a little bit scary.

2) do you need to do the sawing if you buy a 150 PDS?

3) this scope vs a 6 inch RC? any major differences? the thing putting me off the 6 inch RC is the reduced FOV. Is this necessarily an unsurmountable issue?

4) can you please recommend a ccd mono camera that will not under/over sample with this particular set up?

So many questions !!

Thankyou one and all and clear skies !

Andy

HI Andy,

And welcome to the darkside!
1) Maybe yes, maybe No - it all will depend on the camera Focusing distance. If you will get cam in focus with Focuser's Drawtube rolled out a lot, - you will not need to "Circumcise" anything as the drawtube will not cast much shadow on the Primary mirror.

2) 150PDS - the same issue

4) Have you done any imaging before? if not, I would suggest trying any DSLR camera you've got for the start, or the second hand one... As you will spend lots of nights learning things which are not Related to Imaging Directly (guiding, platesolving processing and etc etc). However if you want to skip this part with cheap DSLR and dive directly into MONO, look at something like ZWO ASI1600MM or Similar. Note: for mono camera you will need FilterWheel and Filters, all brand new around £1800 in total.

P.S.

With ASI1600MM you will need to chop off a bit of the drawtube for the Perfect Results, but if you will use Coma Corrector which does not work as Reducer (for example Skywatcher CC is 0.9 reducer) you will be able to live without circumcision as distortion will be quite little, - probably...

"Circumcision" of the drawtube is not the Most challenging task with PDS, in fact, it takes around 10 - 15mins and I doubt someone managed to damage the scope during this procedure. If you will need to, do not chop a lot, go with 1cm first.

The most challenging thing with PDS is collimation of the Secondary Mirror (not Primary, but the smaller one). So if you will get a New One, at the start, adjust just a Primary Mirror if needed, - do  not touch bolts of the secondary at all.

I think this topic should be renamed to "Obsy building Standard"

7 hours ago, bokchoy ninja said:

Can this lens be mounted to a dslr and then supported by that connection alone? In other words can the lens "hang off" a dslr without applying too much stress?

2 hours ago, Knight of Clear Skies said:

Seems to work fine for me, I have the camera body on a ball-head mount so I can frame images to my liking. It's possible that the lens tilts a touch relative to the sensor (AP is much more demanding than daytime photography) but I haven't really noticed.

In opposition, I have tilt with my Canon 1300D if I not support it.

If you check astro pictures from the different users on astrobin or flickr,

you will notice  evidence of the SOME tilt on Some images

So if someone does not have tilt... it does not mean, you will not have it... It is probably very related to camera quality plus Altitude of the target.

However, if you will not able to support it "Properly", - FOV is quite wide with Sammy and you will be able to crop without loosing much data, as I do at the moment

Hahaha  My stepper motor cables are braided in the same manner like yours

Hi Guys,

Has anyone managed to find something like 2" Baader ClickClock or any other 2" eyepiece clamp which would enable to achieve Focus using Canon or ASI1600?

Nah... he leaves no room for EFW and my autofocuser... 

Plus his camera left hanging... I am almost sure it will introduce tilt... I saw one model on his web, were bracket at last Holds ASI1600MM properly,

but this bracket will have no use for my Canon and even EFW!!!

 So if I will need to buy from him, I will end up with 2 brackets and with: + manual focus, +manual filter change.

Not the way I want to go.

My PDS is collimated, not perfect, but Close enough to make me happy  

And we have plenty of Cloudy Nights to make a Proper Bracket with the place for all the automation my toys have and one for both cameras 

2 minutes ago, Helen said:

I bought one last year, but haven't used it in anger yet.  My camera is a Sony A6500 so I bought the Sont fit, even though my plan was to use with the asi1600 mono.  I then got the ZWO adapter, but it was faulyty and had to go back.  I got a replacement, but then realised that because the Sony camera is mirrorless the connector on the lens to chip distance is very short - so no room for a filter wheel - d'oh.  This thread has inspired me to get it set up, particularly as I've picked up a colour asi1600 ?  - or just use it for its designed purpose with my A6500!

 

And finally a request... could people add their configuration, exposure times etc to their images as I think that will help those of us starting out!

Thanks 

Helen

At F2 exposures will be Strongly Location + Camera Dependant isn't it?

I cannot go longer than 30sec @ISO100 with my Canon 1300D in Woolwich.... And ISO100 is very noisy...

Thinking of stepping down to F4, till I manage to print my bracket/holder for ASI1600

19 minutes ago, matt_baker said:

Are all 130's like this is you don't shave a bit off the focuser?

Yep, all Newtonians will have this shadow with Focuser fully in.

I had to circumcise mine also... Not difficult at all, but I cannot use scope for visual after.

Please note, not all cameras are focused on the same spot, - so if you are lucky enough and your camera is focused with focuser Out, your images may not suffer from the shadow at all.

4 hours ago, Atreta said:

hello everyone, i'm trying to get back to using the 130pds as i was struggling to get it collimated. this week i gave the no tools collimation a try and it looks better, but i don't know much about it.

could someone please check if the collimation is ok in this picture?

thanks a lot.

As Carole said,  de-focused star will show all the collimation problems.

Try keeping it in the center of the frame as you do not use Coma Corrector and even the perfect Collimation will look Off if your star will be on the corner or even halfway.

So if you will target a rich star field, central de-focused stars are the ones you need to look at and ignore the ones close/midway to the corners.

Your 8 sec sub has slightly prolonged stars even in the middle.

If you were guiding, - you probably had the tilt of the camera in the focuser, - or guiding was very bad, which I doubt.

So also, keep an eye how you place the camera in, -  it has to be stiff and have no play towards any direction.

4 hours ago, Atreta said:

i was struggling so hard to collimate my 130pds that i gave up imaging with  it for a few months.

recently, i was searching for sites to get some help collimating it and found one that gives a good alternative and it requires no tools to do the job.  I did try this method, but i don't know if my collimation is good or not, i'm about to post an image on the 130pds topic to see if anyone can check it for me.

this is the site: https://garyseronik.com/no-tools-telescope-collimation/   

you could this method a go to check your collimation as you already did it with the barlowed laser and the chesire.

Simply defocus on the star... It is the best way to check

yep... this is what I want to avoid with my All in One bracket...

but I afraid I may tilt it with the motor belt

Anyway, I am sure I will fail from the first attempt

19 hours ago, Space Oddities said:

Rob,

Apparently it's possible to use a belt system to focus this lens. I found one using a Robo focus motor (found on the Deep Sky West remote observatory website):

The Samyang/Rokinon 135mm also exists in a video version (135mm T2.2), which is the same as the f/2 optically, but with a different focusing system. It might be easier to interface the lens with a focusing motor.

However, I believe the aperture ring is clickless, like most video lenses. I'm not sure that's a good thing for astro?

My motor is Nema17PG27, which is a bit smaller and I hope I will manage to place it under the lens.

By the way, while adjusting the lens holding bolts, - how do you know you do not introduce any tilt?

48 minutes ago, Vixen4eva said:

Bought this bracket for my Samyang. Works a treat on my GPDX. Fantastic quality.

Alan

 

Nice!
But I Would not like to leave camera hanging like this... Especially ASI+EWF... 

I am actually in the beginning of modeling a 3D print for Sam135+ASi1600MM+EFW+DIY autofocuser+Guider all in one larger bracket, which will be printed from around 4 parts.

The largest Headache is to keep lens and cam straight, without any tilt, plus I want to avoid any adjustments bolts like usual guider-scopes have. The goal, - Model like: "fit it in and forget it, as all in line, no adjustments needed")......

Also, to place the motor somewhere as low as possible is quite challenging "space-wise and balance-wise"...

Taking into account, I have both left hands  it will take awhile!

But I will try to share my progress if results will be not very miserable!

21 minutes ago, Rush said:

Well , finally the hour of truth has come. i.e the Cheshire CT from TS with CONCENTER tool test. Everything i left untouched from previous tweaking (laser show)

And here s the View through Cheshire CT.

Through Concenter tool, Wonder if i ever will get those  rings aligned with primary to secondary and vice versa cos of the offset ?

An an image after the previous laser tweak. The halo around the bright star is gleaming . Primary edges need tuning ? paint it rough black ? Next adventure ? Thanx much CS,

Rush

2 hrs L and 1 hr RGB with the prvious laser tweak test. Bright star core light streaks around. Sorry if its dirty crude processed , red gradient kill next time after serious extrem imaging:)

 

It looks like you will not be able to see the primary mirror holders via Cheshire just like me!
Have fun!  hehe

I hope I am not right  as this makes life much more difficult....

I even tried to place my ASI224MC directly into the draw-tube, as 224MC body is actually 2" and it fits perfectly,

but... I did not like what I saw... Still cannot understand why the view was of-center...
Will repeat it next week will post some pics.

Nice...

The reply to my email was, - price is not known for UK till Brexit as taxation is not yet clear.

P.S.

Lets hope he will also add some USB slots and I would be happy to test it for Free!  hehehehe

heh

These are the results of proper tools in proper hands!!! 

I have both left hands I think... 
My result from only 2 sessions I managed to have using my Canon 1300D from London...

I found it Very difficult to process...

Very Nice SteamPunk style Dome!
Enjoyed to read from A to Z  

Especially to see how the motor suspension solution works

Thanks a lot for sharing!

P.S.
Will you automate the roll off roof also?

19 minutes ago, souls33k3r said:

Not a bad shout mate but i've had a really bad experience with one of these bad boys just last summer. I was out having a nice lunch with the family, a gust of wind came and blew it across 2 houses

The main word was a "Camouflage"
You can reinforce it just like the pier!  And use a hail-proof Kevlar if needed!

Plus, the "Flight" yours had, probably was while it was wide open

Newtonian dual rig is possible, but... very very tricky to balance.... Keep in mind, your camera will be on the TOP end of the OTA...

Refractors, are much easier in this case as all the weight is at the bottom and central.

First of all, you will most likely need OAG, I tried to balance my 130PDS with Samyang 135mm+Canon on top and a SW 50ED guider... On NEQ6... No luck...

plus if you will add autofocuser with a direct shaft connection, without the pulley,

you will need to add quite a lot of weight at the bottom of the OTA, otherwise autofocuser will not fit, dovetail will be in the way (check my image carefully).

And lastly,

Even if I have managed to balance mine, - I am not completely happy...

The setup became very, Very sensitive on guiding... I do not have constant guiding results now.. A bit worse seeing conditions and the PHD graph is all other the place... and my mount is NEQ6 not HEQ5...

I do not say it is not possible in your case, - just sharing my experience.