new filter wheel

[Fieldsy]

Motorised filter wheel arrived today 🥳 have gone for

1,uv/ir (for now) 2, red 3,green 4,blue 5,ha7nm.

I seem to struggle getting a good focus with a batinhov mask and the asiair, anyone else having issues ?

 

 

[Adam J]

2 minutes ago, Fieldsy said:

Motorised filter wheel arrived today 🥳 have gone for

1,uv/ir (for now) 2, red 3,green 4,blue 5,ha7nm.

I seem to struggle getting a good focus with a batinhov mask and the asiair, anyone else having issues ?

 

 

can you post an example star field? This would really help.

The mask should give good results so it might just be the asi air tool.

You can use it manually and just place the center spike between the other two...usually not much worse by eye than with the aid.

Expect to have to guide for a good 10 seconds to get a good focus with the Ha filter. Or as they are all baader then you can also use the red to focus and then change to the ha.

Please post an image of your stars though as that will help me help you.

Adam

 

[Fieldsy]

10 minutes ago, Adam J said:

can you post an example star field? This would really help.

The mask should give good results so it might just be the asi air tool.

You can use it manually and just place the center spike between the other two...usually not much worse by eye than with the aid.

Expect to have to guide for a good 10 seconds to get a good focus with the Ha filter. Or as they are all baader then you can also use the red to focus and then change to the ha.

Please post an image of your stars though as that will help me help you.

Adam

 

Took a set of 150 images at 15 secs on M3 could see a blur of the cluster but DSs only wants to stack 1 images.

[Demonperformer]

5 hours ago, Fieldsy said:

DSs only wants to stack 1 images

Common problem. Try lowering the threshold. Alternatively, try capturing using Sharpcap, which will stack your subs as it goes along (saves disk space, and all that tedious messing about with DSS!)

[Adam J]

9 hours ago, Fieldsy said:

Took a set of 150 images at 15 secs on M3 could see a blur of the cluster but DSs only wants to stack 1 images.

Like I say if you, post a single sub then it will be easy to diagnose. Just stack a single sub get the output as a tif and stretch it in photoshop or whatever you are using to image. 

As above so long as the stars are not very very far out of focus then DSS should stack them, it means that the star detection threshold is set too low you can lower it until you get about 50-100 stars detected.

Adam  

[Fieldsy]

13 hours ago, Adam J said:

Like I say if you, post a single sub then it will be easy to diagnose. Just stack a single sub get the output as a tif and stretch it in photoshop or whatever you are using to image. 

As above so long as the stars are not very very far out of focus then DSS should stack them, it means that the star detection threshold is set too low you can lower it until you get about 50-100 stars detected.

Adam  

only one it wants to stack 

Light_M101_5sec_frame0004_gain50.fit

[Adam J]

57 minutes ago, Fieldsy said:

only one it wants to stack 

Light_M101_5sec_frame0004_gain50.fit 12.29 MB · 2 downloads

So this is what it looks like with some quick stretching.

So first the good news. You have M3 its recognizable as such and its nailed in the center of the frame. Everything is working with the camera and the exposure is about right. I might notch the gain up to 120 though with a 15 second exposure.  So congratulations you have officially taken an image of m3 that you can call your first DSO image and if you had been able to stack all 150 frames i am sure it would have been a cracker.

Now the bad news....

You have two problems:

1) Your 130pds is clearly a long long way out of colimation as you have some serious coma going on right in the center of the image. This alone might give DSS issues with aligning frames as the stars are not point sources.

2) You are indeed also out of focus, this is most likely due to the bad colimation causing the focusing mask to not function correctly.

It is unlikely that DSS will be pursuaded to register the other frames due to these issues. This frames has simply been selected as the only frame as it has the highest quality score.

So I think this is good progress and you are very close to victory. You "just" need to colimate the scope. I am assuming that you have something like a Cheshire or a laser colimator or ideally both? Is this something that you have tried before? Or is the scope just as it came from skywatcher?

Fix the colimation, get good focus and repeat exactly what you just did when capturing and you will have cracked it.

Adam

 

 

 

[Fieldsy]

29 minutes ago, Adam J said:

So this is what it looks like with some quick stretching.

So first the good news. You have M3 its recognizable as such and its nailed in the center of the frame. Everything is working with the camera and the exposure is about right. I might notch the gain up to 120 though with a 15 second exposure.  So congratulations you have officially taken an image of m3 that you can call your first DSO image and if you had been able to stack all 150 frames i am sure it would have been a cracker.

Now the bad news....

You have two problems:

1) Your 130pds is clearly a long long way out of colimation as you have some serious coma going on right in the center of the image. This alone might give DSS issues with aligning frames as the stars are not point sources.

2) You are indeed also out of focus, this is most likely due to the bad colimation causing the focusing mask to not function correctly.

It is unlikely that DSS will be pursuaded to register the other frames due to these issues. This frames has simply been selected as the only frame as it has the highest quality score.

So I think this is good progress and you are very close to victory. You "just" need to colimate the scope. I am assuming that you have something like a Cheshire or a laser colimator or ideally both? Is this something that you have tried before? Or is the scope just as it came from skywatcher?

Fix the colimation, get good focus and repeat exactly what you just did when capturing and you will have cracked it.

Adam

 

 

 

🥳🥳🥳 Hi Adam I do a collimation every start up with laser and put the light into the middle every time ,I have noticed the black circle (looks out of focus) in the top left and have never managed to loose it . I have also had to trim 6 mm of the 2inch - to1.25 adapter to get the required interval for focus seems to be good now ,have also gone back to eqmod platesolve has worked well three different images all good and the tracking ra/dec have reduced to x1 and seems to be a bit more acceptable.not sure what more I can do for the collimation if the laser in in the centre I did just presume that was it.

[Adam J]

10 hours ago, Fieldsy said:

🥳🥳🥳 Hi Adam I do a collimation every start up with laser and put the light into the middle every time ,I have noticed the black circle (looks out of focus) in the top left and have never managed to loose it . I have also had to trim 6 mm of the 2inch - to1.25 adapter to get the required interval for focus seems to be good now ,have also gone back to eqmod platesolve has worked well three different images all good and the tracking ra/dec have reduced to x1 and seems to be a bit more acceptable.not sure what more I can do for the collimation if the laser in in the centre I did just presume that was it.

The black circle is just dust, most likely on the filter. That is a normal issue for everyone and fixed with flat frames but don't worry about it for now / forget about it entirely until you have sorted some other still out.  

In terms of focus I assume you are using a very bright star to focus before panning to your target? I also assume that plate solving worked as you managed to get the target in view? Given the focus issue that is actually quite impressive if true. 

So when you say the light in the middle I assume you mean both the laser in the centre spot of the primary mirror and also the reflection of the laser in the centre of the target on the laser collimator? Adjusting the former with the three secondary screws on the spider and the latter with the adjustment screws and locking screws on the primary. 

When you say that you chopped down the 2 inch to 1.25 inch reducer two things come to mind:

1) can you be sure that the cut you made (presumably on to 1.25inch side) 100% parallel to the 2 inch side. If not then it will cause very bad tilt. 

2) is it the original skywatcher 2 inch to 1.25 inch reducer? If so then when I got mine I found that it was not square in the first place. 

When connecting with a larger sensor you would require a coma corrector that would fit into the 2 inch holder and have either a M48 or M42 (T2) thread on the camera side. Your sensor may be small enough not to require a coma corrector, however its still important how you connect it to the scope.  When connecting any sensor to a Newtonian its critical that the sensor sits flush to the focuser (same for the laser) as the laser colimation is only valid if neither are tilted, with your method of connection you have three thumb screws attachments (2 inch to 1.25 inch, 1.25 inch to filter wheel and camera 1.25 inch to filter wheel) and potentially a dodgy 2 inch to 1.25 inch connection. Thumb screw attachments are not ideal in any case let alone three of them. However my betting is that the main issue is the 1.25 inch to 2 inch that you cut down.  

So the correct way to connect is as follows:

        a) Take the camera and remove the 1.25 inch nose piece. 

        b) Take the T2-T2 (male to male) adaptor and thread it onto the camera in place of the 1.25 inch nose piece. 

        c) Remove the 1.25 inch holder from the back side of the filter wheel (the opposite side to the one that the filters screw down from).

        d) thread the other side of the T2-T2 adaptor directly onto the filter wheel to connect the camera. (this will move the camera closer to the scope removing the focusing issue you had. 

        e) You can now do one of two things. i) Purchase a better quality (compression ring) 1.25 to 2 inch eyepiece adaptor (do this if your laser is 1.25 inch only). ii) Purchase a 2 inch nose to T2 adaptor to allow you to thread the filter wheel directly to the 2 inch connection and forgo the 1.25 to 2 inch adaptor entirely (this is the correct and best way to connect to the scope and ideally you would use this method in addition to purchasing the 1.25 inch to 2 inch adaptor for the laser if required as it will again move the camera towards the scope helping you achieve focus)........so more money. 

Note: A laser alone cant guarantee correct collimation as you cant ensure that the secondary mirror is centred in the focusing tube. For this you need a Cheshire colimaror or a colimation cap. However so long as you have not messed with the centre bolt on the secondary mirror this is usually set correctly when you receive the scope. 

I am certain of one thing however, your colimation is out and so if you are colimating correctly its a issue of tilt in your adaptors. 

Adam 

 

 

 

[Fieldsy]

3 hours ago, Adam J said:

The black circle is just dust, most likely on the filter. That is a normal issue for everyone and fixed with flat frames but don't worry about it for now / forget about it entirely until you have sorted some other still out.  

In terms of focus I assume you are using a very bright star to focus before panning to your target? I also assume that plate solving worked as you managed to get the target in view? Given the focus issue that is actually quite impressive if true. 

So when you say the light in the middle I assume you mean both the laser in the centre spot of the primary mirror and also the reflection of the laser in the centre of the target on the laser collimator? Adjusting the former with the three secondary screws on the spider and the latter with the adjustment screws and locking screws on the primary. 

When you say that you chopped down the 2 inch to 1.25 inch reducer two things come to mind:

1) can you be sure that the cut you made (presumably on to 1.25inch side) 100% parallel to the 2 inch side. If not then it will cause very bad tilt. 

2) is it the original skywatcher 2 inch to 1.25 inch reducer? If so then when I got mine I found that it was not square in the first place. 

When connecting with a larger sensor you would require a coma corrector that would fit into the 2 inch holder and have either a M48 or M42 (T2) thread on the camera side. Your sensor may be small enough not to require a coma corrector, however its still important how you connect it to the scope.  When connecting any sensor to a Newtonian its critical that the sensor sits flush to the focuser (same for the laser) as the laser colimation is only valid if neither are tilted, with your method of connection you have three thumb screws attachments (2 inch to 1.25 inch, 1.25 inch to filter wheel and camera 1.25 inch to filter wheel) and potentially a dodgy 2 inch to 1.25 inch connection. Thumb screw attachments are not ideal in any case let alone three of them. However my betting is that the main issue is the 1.25 inch to 2 inch that you cut down.  

So the correct way to connect is as follows:

        a) Take the camera and remove the 1.25 inch nose piece. 

        b) Take the T2-T2 (male to male) adaptor and thread it onto the camera in place of the 1.25 inch nose piece. 

        c) Remove the 1.25 inch holder from the back side of the filter wheel (the opposite side to the one that the filters screw down from).

        d) thread the other side of the T2-T2 adaptor directly onto the filter wheel to connect the camera. (this will move the camera closer to the scope removing the focusing issue you had. 

        e) You can now do one of two things. i) Purchase a better quality (compression ring) 1.25 to 2 inch eyepiece adaptor (do this if your laser is 1.25 inch only). ii) Purchase a 2 inch nose to T2 adaptor to allow you to thread the filter wheel directly to the 2 inch connection and forgo the 1.25 to 2 inch adaptor entirely (this is the correct and best way to connect to the scope and ideally you would use this method in addition to purchasing the 1.25 inch to 2 inch adaptor for the laser if required as it will again move the camera towards the scope helping you achieve focus)........so more money. 

Note: A laser alone cant guarantee correct collimation as you cant ensure that the secondary mirror is centred in the focusing tube. For this you need a Cheshire colimaror or a colimation cap. However so long as you have not messed with the centre bolt on the secondary mirror this is usually set correctly when you receive the scope. 

I am certain of one thing however, your colimation is out and so if you are colimating correctly its a issue of tilt in your adaptors. 

Adam 

 

 

 

Re camera to filter wheel yes I use the t2/t2 straight in to wheel then 1.25 nose in to 2/1.25 focused, the 1.25 thumb screw had a 5mm lip that's what I took of.i had a good look this morn on the collimation and yes the laser was off by about a inch on the back mirror so I've adjusted that now ( not as easy as adjusting the back mirror) but all looks ok .so next possible outing is tuesday🤞🏻

[Adam J]

5 minutes ago, Fieldsy said:

Re camera to filter wheel yes I use the t2/t2 straight in to wheel then 1.25 nose in to 2/1.25 focused, the 1.25 thumb screw had a 5mm lip that's what I took of.i had a good look this morn on the collimation and yes the laser was off by about a inch on the back mirror so I've adjusted that now ( not as easy as adjusting the back mirror) but all looks ok .so next possible outing is tuesday🤞🏻

Not sure what you mean by "1.25 thumb screw had a 5mm lip that's what I took of" can you take a picture. 

One test I highly recommend that you do is to rotate the laser and 1.25inch / 2 inch adapter within the focuser. If the laser dot moves in a circle instead of staying in the same place as you rotate (give or take a couple of milimeters) then the adapter or laser is tilted and you will never achieve good colimation. 

I ask because it being 1 inch out is a long way and it makes me wonder if its because you inserted the laser in a different orientation to when you last colimated the scope. 

You are looking for millimetre accuracy when colimating as opposed to inch accuracy lol. 

Adam 

[Fieldsy]

15 minutes ago, Adam J said:

Not sure what you mean by "1.25 thumb screw had a 5mm lip that's what I took of" can you take a picture. 

One test I highly recommend that you do is to rotate the laser and 1.25inch / 2 inch adapter within the focuser. If the laser dot moves in a circle instead of staying in the same place as you rotate (give or take a couple of milimeters) then the adapter or laser is tilted and you will never achieve good colimation. 

I ask because it being 1 inch out is a long way and it makes me wonder if its because you inserted the laser in a different orientation to when you last colimated the scope. 

You are looking for millimetre accuracy when colimating as opposed to inch accuracy lol. 

Adam 

1.25 thumb screw ,meant the locking screw on the 1.25 side of the 2-1.25 reducer. Collimator when I placed the laser into the 2-1.25 reducer the laser dot was about a inch from the circle in the middle of the second mirror so I’ve now centralised it in the circle and adjust so the laser point is in the middle whole on the collimator , work has now been cancelled (how cool is that😃) so may be out tonight. 

[Adam J]

5 minutes ago, Fieldsy said:

1.25 thumb screw ,meant the locking screw on the 1.25 side of the 2-1.25 reducer. Collimator when I placed the laser into the 2-1.25 reducer the laser dot was about a inch from the circle in the middle of the second mirror so I’ve now centralised it in the circle and adjust so the laser point is in the middle whole on the collimator , work has now been cancelled (how cool is that😃) so may be out tonight. 

Good luck, I still recommend that you try the rotation test to check that the laser is running parallel to the focuser. 

[Fieldsy]

3 hours ago, Adam J said:

Good luck, I still recommend that you try the rotation test to check that the laser is running parallel to the focuser. 

Well I tried twisting collimation and it moves up 10mm but it always seem loose until u tighten up thumb screws x3

[Adam J]

1 hour ago, Fieldsy said:

Well I tried twisting collimation and it moves up 10mm but it always seem loose until u tighten up thumb screws x3

So as you rotated it the laser on the mirror moved buy up to 10mm away from the spot? 

If so that's no good I am sorry to say. The surface on that adaptor needs to be very flat to give consistent collimation results. I went so far as to glue my laser into the adaptor to prevent it moving as I tighten the thumb screw. But that relies on the adaptor being nice and flat. 

Just to be sure you are rotating the entire laser and adaptor within the focuser through 360 and noting how much the dot moves as you rotated? 

I think a better quality adapter may be required along with a 2 inch T2 nose piece. But try it again tonight and see what happens. 

Adam 

[Fieldsy]

3 hours ago, Adam J said:

So as you rotated it the laser on the mirror moved buy up to 10mm away from the spot? 

If so that's no good I am sorry to say. The surface on that adaptor needs to be very flat to give consistent collimation results. I went so far as to glue my laser into the adaptor to prevent it moving as I tighten the thumb screw. But that relies on the adaptor being nice and flat. 

Just to be sure you are rotating the entire laser and adaptor within the focuser through 360 and noting how much the dot moves as you rotated? 

I think a better quality adapter may be required along with a 2 inch T2 nose piece. But try it again tonight and see what happens. 

Adam 

2 inch adapter is very loose if thumb screws not used

[Adam J]

29 minutes ago, Fieldsy said:

2 inch adapter is very loose if thumb screws not used

I know you have to push it in as you turn, or tighten the thumb screws at each quarter turn and examination the result.