Dual Wielding a 10" Dob and 4" APO 17/09/2024

[Ratlet]

I did a bit of prep this time and checked the jet stream forecast which showed that it would be well north, even of me.  Clearoutside predicted high cloud, but from experience I know that this can be complete coverage but thin.  In the dim and distant I was afforded one of my best views of Mars under similar circumstances (where the thin cloud acted as a filter to tone down the brightness.  As such I figured that the best thing to do would be to do a comparison between the 4" 102ED and the 10" StellaLyra Dob.

The reason for this is two fold.  One is to just see what a difference it can make in aperture and secondly it's to see how good collimation can be achieved using a cheap laser collimator.

As I kicked of the evening I pulled out the cheap laser collimator dropped it in and gave it a little bit of a spin.  The laser did a circle on the primary.  Not ideal.  I resorted to using my 2x BST barlow with the collimator.  This is a slightly different method for collimating but can eliminate any errors from miscollimation of the laser.  Instead of reflected laser dot you get a reflected circle from centre circle on the primary.  Job done.

I got the 102ED setup with my 12mm x60 and was rewarded with some very satisfying diffraction rings.  This would be the last time I did a start test and the last time I used the 12mm for the evening.  I should have done one to check the collimation on the dob, but..

I swung the 102ED on to Jupiter and imedately swapped out the 12mm for the 3-8mm SVBONY zoom with a moon and skyglow filter and a yellow filter, paired together to improve contrast.  At 8mm (x90) it was obvious that the seeing was good.  I could just make out a moon hovering above one of the poles (Titan).  Some banding faintly visible along with the very slight gap of the rings.  Increwasing to 5mm (x142) and Titan was clearer and more detail evident in the planet as well as the rings.  Another moon also became apparent (Rhea).  Deciding to push my luck I increased to 3mm (x238).  The view was frankly spectacular.  I could now see the shadow of the rings.

At this point I swapped over to the dob with the same eyepiece setup, returning to 8mm (x156).  The view was, objectively 'mental'  the detail was absolutely incredible.  Like a photograph.  Titan and Rhea were obvious now and a third moon had popped into view (Tethys).  Again I jumped up to 5mm (x250) and was rewarded with yet another moon (Dione).  Going for broke I pushed it to 3mm (x400) and honestly the seeing was supporting it, but I think I was at the limit visually.  Further there is no tracking on the dob so keeping things centred (or rather drifting past the FOV) was tiresome, so I went back to 5mm.  I will say that for all the drifting through the FOV everything stayed nicely sharp.

I'd like to say I had more written down, but I got lost in the evening and spent about 3 hours bouncing back and forth between the 2 scopes.  The Dob had incredible detail but the 102ED wasn't too far behind and had the advantage of tracking.  I managed to get my mobile attached and honestly I'm delighted with the quality even if it isn't a patch on what I actually saw.

Some other observations:

• First time I used the dew heater.  Needed it on the finderscope on the Dob as the Dew was pretty wild.  Oddly the Dob was hit hard but the 102ED didn't seem as damp.
• The dob can obviously provide more detail, but in terms of a relaxed and enjoyable experience (at high power) the 102ED wins.
• At high power both of my scopes would possibly benefit with an electronic focuser.  The vibrations from adjusting focus makes it a pain to try and get the perfect focus sometimes.  Other times it just seemed to 'snap to' focus.

At the end of the evening (morning by this point) the promised high cloud arrived but was thicker than I would have liked.  Jupiter vanishing completely to the naked eye. I decided to try for Jupiter as the GRS was front and centre.  I had to move the dob twice and I think the collimation might have taken a hit as the view just wasn't great.  I did however manage to see the GRS for the first time which was nice.  I would have liked a bit more detail, but honestly that feels like being greedy at this point.

I've often wondered how people can spend and entire evening on the planets.  Now I get it.  It was fantastic and the time just vanished.  I'll try again tonight, but this time go for an 0300 start and work on Mars and Jupiter.  I might take out the 130PDS and 102ED as it should be more interesting to see how these two compare.

[PeterStudz]

A couple of years ago we did (well, have done a few similar) an all night session on the planets with my daughter - Saturn, Jupiter, Neptune, Uranus and Mars - while camping out in the garden. Also included white light solar after a camp breakfast. Tremendous fun and a great thing to do with kids if they are also into astronomy. 

[bosun21]

2 hours ago, Ratlet said:

I did a bit of prep this time and checked the jet stream forecast which showed that it would be well north, even of me.  Clearoutside predicted high cloud, but from experience I know that this can be complete coverage but thin.  In the dim and distant I was afforded one of my best views of Mars under similar circumstances (where the thin cloud acted as a filter to tone down the brightness.  As such I figured that the best thing to do would be to do a comparison between the 4" 102ED and the 10" StellaLyra Dob.

The reason for this is two fold.  One is to just see what a difference it can make in aperture and secondly it's to see how good collimation can be achieved using a cheap laser collimator.

As I kicked of the evening I pulled out the cheap laser collimator dropped it in and gave it a little bit of a spin.  The laser did a circle on the primary.  Not ideal.  I resorted to using my 2x BST barlow with the collimator.  This is a slightly different method for collimating but can eliminate any errors from miscollimation of the laser.  Instead of reflected laser dot you get a reflected circle from centre circle on the primary.  Job done.

I got the 102ED setup with my 12mm x60 and was rewarded with some very satisfying diffraction rings.  This would be the last time I did a start test and the last time I used the 12mm for the evening.  I should have done one to check the collimation on the dob, but..

I swung the 102ED on to Jupiter and imedately swapped out the 12mm for the 3-8mm SVBONY zoom with a moon and skyglow filter and a yellow filter, paired together to improve contrast.  At 8mm (x90) it was obvious that the seeing was good.  I could just make out a moon hovering above one of the poles (Titan).  Some banding faintly visible along with the very slight gap of the rings.  Increwasing to 5mm (x142) and Titan was clearer and more detail evident in the planet as well as the rings.  Another moon also became apparent (Rhea).  Deciding to push my luck I increased to 3mm (x238).  The view was frankly spectacular.  I could now see the shadow of the rings.

At this point I swapped over to the dob with the same eyepiece setup, returning to 8mm (x156).  The view was, objectively 'mental'  the detail was absolutely incredible.  Like a photograph.  Titan and Rhea were obvious now and a third moon had popped into view (Tethys).  Again I jumped up to 5mm (x250) and was rewarded with yet another moon (Dione).  Going for broke I pushed it to 3mm (x400) and honestly the seeing was supporting it, but I think I was at the limit visually.  Further there is no tracking on the dob so keeping things centred (or rather drifting past the FOV) was tiresome, so I went back to 5mm.  I will say that for all the drifting through the FOV everything stayed nicely sharp.

I'd like to say I had more written down, but I got lost in the evening and spent about 3 hours bouncing back and forth between the 2 scopes.  The Dob had incredible detail but the 102ED wasn't too far behind and had the advantage of tracking.  I managed to get my mobile attached and honestly I'm delighted with the quality even if it isn't a patch on what I actually saw.

Some other observations:

• First time I used the dew heater.  Needed it on the finderscope on the Dob as the Dew was pretty wild.  Oddly the Dob was hit hard but the 102ED didn't seem as damp.
• The dob can obviously provide more detail, but in terms of a relaxed and enjoyable experience (at high power) the 102ED wins.
• At high power both of my scopes would possibly benefit with an electronic focuser.  The vibrations from adjusting focus makes it a pain to try and get the perfect focus sometimes.  Other times it just seemed to 'snap to' focus.

At the end of the evening (morning by this point) the promised high cloud arrived but was thicker than I would have liked.  Jupiter vanishing completely to the naked eye. I decided to try for Jupiter as the GRS was front and centre.  I had to move the dob twice and I think the collimation might have taken a hit as the view just wasn't great.  I did however manage to see the GRS for the first time which was nice.  I would have liked a bit more detail, but honestly that feels like being greedy at this point.

I've often wondered how people can spend and entire evening on the planets.  Now I get it.  It was fantastic and the time just vanished.  I'll try again tonight, but this time go for an 0300 start and work on Mars and Jupiter.  I might take out the 130PDS and 102ED as it should be more interesting to see how these two compare.

You should either build yourself or buy an equatorial platform for the dobsonian. That way you get to keep all the benefits of the extra aperture and without the constant nudging. It was a game changer when I bought one for my 12" SL dobsonian. The only scope I don't mind using without any tracking is my G&G 80ED refractor as I'm usually observing somewhat wide field. An electric focuser is also a blessing at high magnification planetary work.

[TiffsAndAstro]

2 hours ago, Ratlet said:

I did a bit of prep this time and checked the jet stream forecast which showed that it would be well north, even of me.  Clearoutside predicted high cloud, but from experience I know that this can be complete coverage but thin.  In the dim and distant I was afforded one of my best views of Mars under similar circumstances (where the thin cloud acted as a filter to tone down the brightness.  As such I figured that the best thing to do would be to do a comparison between the 4" 102ED and the 10" StellaLyra Dob.

The reason for this is two fold.  One is to just see what a difference it can make in aperture and secondly it's to see how good collimation can be achieved using a cheap laser collimator.

As I kicked of the evening I pulled out the cheap laser collimator dropped it in and gave it a little bit of a spin.  The laser did a circle on the primary.  Not ideal.  I resorted to using my 2x BST barlow with the collimator.  This is a slightly different method for collimating but can eliminate any errors from miscollimation of the laser.  Instead of reflected laser dot you get a reflected circle from centre circle on the primary.  Job done.

I got the 102ED setup with my 12mm x60 and was rewarded with some very satisfying diffraction rings.  This would be the last time I did a start test and the last time I used the 12mm for the evening.  I should have done one to check the collimation on the dob, but..

I swung the 102ED on to Jupiter and imedately swapped out the 12mm for the 3-8mm SVBONY zoom with a moon and skyglow filter and a yellow filter, paired together to improve contrast.  At 8mm (x90) it was obvious that the seeing was good.  I could just make out a moon hovering above one of the poles (Titan).  Some banding faintly visible along with the very slight gap of the rings.  Increwasing to 5mm (x142) and Titan was clearer and more detail evident in the planet as well as the rings.  Another moon also became apparent (Rhea).  Deciding to push my luck I increased to 3mm (x238).  The view was frankly spectacular.  I could now see the shadow of the rings.

At this point I swapped over to the dob with the same eyepiece setup, returning to 8mm (x156).  The view was, objectively 'mental'  the detail was absolutely incredible.  Like a photograph.  Titan and Rhea were obvious now and a third moon had popped into view (Tethys).  Again I jumped up to 5mm (x250) and was rewarded with yet another moon (Dione).  Going for broke I pushed it to 3mm (x400) and honestly the seeing was supporting it, but I think I was at the limit visually.  Further there is no tracking on the dob so keeping things centred (or rather drifting past the FOV) was tiresome, so I went back to 5mm.  I will say that for all the drifting through the FOV everything stayed nicely sharp.

I'd like to say I had more written down, but I got lost in the evening and spent about 3 hours bouncing back and forth between the 2 scopes.  The Dob had incredible detail but the 102ED wasn't too far behind and had the advantage of tracking.  I managed to get my mobile attached and honestly I'm delighted with the quality even if it isn't a patch on what I actually saw.

Some other observations:

• First time I used the dew heater.  Needed it on the finderscope on the Dob as the Dew was pretty wild.  Oddly the Dob was hit hard but the 102ED didn't seem as damp.
• The dob can obviously provide more detail, but in terms of a relaxed and enjoyable experience (at high power) the 102ED wins.
• At high power both of my scopes would possibly benefit with an electronic focuser.  The vibrations from adjusting focus makes it a pain to try and get the perfect focus sometimes.  Other times it just seemed to 'snap to' focus.

At the end of the evening (morning by this point) the promised high cloud arrived but was thicker than I would have liked.  Jupiter vanishing completely to the naked eye. I decided to try for Jupiter as the GRS was front and centre.  I had to move the dob twice and I think the collimation might have taken a hit as the view just wasn't great.  I did however manage to see the GRS for the first time which was nice.  I would have liked a bit more detail, but honestly that feels like being greedy at this point.

I've often wondered how people can spend and entire evening on the planets.  Now I get it.  It was fantastic and the time just vanished.  I'll try again tonight, but this time go for an 0300 start and work on Mars and Jupiter.  I might take out the 130PDS and 102ED as it should be more interesting to see how these two compare.

dw a 2h and a 1h? must be the new warcraft patch

[Ratlet]

[PeterStudz]

21 minutes ago, bosun21 said:

You should either build yourself or buy an equatorial platform for the dobsonian. That way you get to keep all the benefits of the extra aperture and without the constant nudging. It was a game changer when I bought one for my 12" SL dobsonian. The only scope I don't mind using without any tracking is my G&G 80ED refractor as I'm usually observing somewhat wide field. An electric focuser is also a blessing at high magnification planetary work.

I agree. If something happened to my EQ platform I’d immediately build another. With far less nudging it also helps me to relax at the eyepiece. When I’m relaxed I see more. It’s also easy to forget that observing takes practice. Beginners often think that looking through an eyepiece is like looking at a computer screen - one quick glance and you’ve seen it all. One reason that I spend so long looking at the planets (Mars is a good example) is to learn how to see more. The more time I spend looking the more I can see. And not just during that session. Once familiar with a target you can potentially see more and see more on another night. 

[Ratlet]

2 minutes ago, PeterStudz said:

I agree. If something happened to my EQ platform I’d immediately build another. With far less nudging it also helps me to relax at the eyepiece. When I’m relaxed I see more. It’s also easy to forget that observing takes practice. Beginners often think that looking through an eyepiece is like looking at a computer screen - one quick glance and you’ve seen it all. One reason that I spend so long looking at the planets (Mars is a good example) is to learn how to see more. The more time I spend looking the more I can see. And not just during that session. Once familiar with a target you can potentially see more and see more on another night. 

Matches my experience completely.  Observation isn't looking, it is a skill.  I think everyone who starts visual should start sketching at the same time.  You really spend the time observing and looking around the fov.  This also has the benefit of getting your averted vision going.

I've got plans almost done and pretty much all the parts except for the aluminium for the sectors and the steel rod for the drive to build an EQ platform.  It's been somewhat on hold as I've been building the skills with Arduino to make one and finishing off a summer house which will be clad internally in plywood (I'm tight as a ducks and I'll order all the wood at once to save on shipping.  Also to disguise it's arrival).

An alternative which looks attractive and I might just do as a project is building an onstep setup for goto and tracking.

[bosun21]

6 minutes ago, PeterStudz said:

I agree. If something happened to my EQ platform I’d immediately build another. With far less nudging it also helps me to relax at the eyepiece. When I’m relaxed I see more. It’s also easy to forget that observing takes practice. Beginners often think that looking through an eyepiece is like looking at a computer screen - one quick glance and you’ve seen it all. One reason that I spend so long looking at the planets (Mars is a good example) is to learn how to see more. The more time I spend looking the more I can see. And not just during that session. Once familiar with a target you can potentially see more and see more on another night. 

Yes indeed. Looking through an eyepiece and observing is a skill that needs to be learned. Spending time at the eyepiece is essential.

[John]

19 minutes ago, PeterStudz said:

....It’s also easy to forget that observing takes practice. Beginners often think that looking through an eyepiece is like looking at a computer screen - one quick glance and you’ve seen it all. One reason that I spend so long looking at the planets (Mars is a good example) is to learn how to see more. The more time I spend looking the more I can see. And not just during that session. Once familiar with a target you can potentially see more and see more on another night. 

Very true indeed !

 

[PeterStudz]

3 hours ago, Ratlet said:

Matches my experience completely.  Observation isn't looking, it is a skill.  I think everyone who starts visual should start sketching at the same time.  You really spend the time observing and looking around the fov.  This also has the benefit of getting your averted vision going.

I have tried sketching and occasionally still do it. Although I’m terrible at it. Pencils and bits drop onto the grass and/or get eaten by the dog. I tear or make holes in the paper. I find it hard to see what I’m doing… but I’m sure it’s just practice. It’s one reason I do smartphone images. Overall I’m not trying to produce astrophotography. If I have time at the end of a night I use the images to help record and document what I’ve seen. Sometimes doodling directly onto the image. After I finish and go inside I try and write a little report directly alongside/within the image in the Caption area. I find that this helps reinforce what I’ve seen. It’s also great to look back at and see how far I’ve come.

PS - great report which I enjoyed reading. I thought I’d mention that before… probably old age!

Edited September 18 by PeterStudz