EdgeHD, just how much bigger is the 9.25 inch compared to the 8 inch

[fifeskies]

I am swapping over from an 8 inch EdgeHD to a 9.25 inch EdgeHD.

I carefully researched to check sizes and weights, but there were few comparison photos about.

Here are the 2 mid transition.

8 on the way out 9.25 on the way in.

 

There is a big step up in overall size with the 9.25 despite it only being a little bigger on aperture.

 

 

[Elp]

But how much more effort it is to put the larger one on the mount unaided?

[fifeskies]

1 hour ago, Elp said:

But how much more effort it is to put the larger one on the mount unaided?

This will live on a permanent pier in a dome so it's not such an issue for me. 

Would not want to be setting this up and taking it down each time.

[Stu]

5 hours ago, fifeskies said:

There is a big step up in overall size with the 9.25 despite it only being a little bigger on aperture.

As I recall, the 925 uses an f2.5 primary vs f2 for the rest of the range, that’s why it is so much longer than you expect it should be.

[Nakedgun]

32 minutes ago, fifeskies said:

This will live on a permanent pier in a dome so it's not such an issue for me. 

Would not want to be setting this up and taking it down each time.

~

Hardly anything compared to the C-14 I used to heft up onto a G-11 every use. That one is gone about 20 years now, and my back is grateful.

 

 

.

Edited April 14 by Nakedgun

[fifeskies]

12 hours ago, Stu said:

As I recall, the 925 uses an f2.5 primary vs f2 for the rest of the range, that’s why it is so much longer than you expect it should be.

The f2.5 primary (and so the longer OTA) has a particular benefit for this system when loaded with an OAG and ZWO camera train.

I no longer need as much front counterbalance weight for the system.

I was using 2kg front weight on my EdgeHD 8 to get it to balance.

 

The Edge HD 9.25 imaging system can balance  without any front weight, as long as it sits towards the rear of the Losmandy. (with metal dewshield added.)

This means the overall mount load for the HD 9.25 is actually only around 1.5kg heavier than for the HD 8, even though the OTA itself is 3kg heavier.

It is around 14.5Kg all in (with 2nd Losmandy on top and a telrad).

(The top losmandy provides adequate front counterweight).

 

 

Edited April 15 by fifeskies

[Simon Pepper]

I have a 9.25 on the way and I am so excited. Will you use bobs knobs or do they hold colimation well? Thanks 

[fifeskies]

9 minutes ago, Simon Pepper said:

I have a 9.25 on the way and I am so excited. Will you use bobs knobs or do they hold colimation well? Thanks 

Its new to me so cant say how they hold collimation , however I have a set of Bob's Knobs to fit to it just in case.

My 8 never drifted so I guess they are fine , tho mine lived in a dome on a permanent mount which no doubt helps it stay good as its not ever moved about.

[Simon Pepper]

Makes sense. I don’t have a permanent setup yet but I am working on that. It will be my first SCT though so lots to learn I am sure after the initial excitement. Do you image with the reducer or use it at native? Thanks 

[fifeskies]

3 minutes ago, Simon Pepper said:

Makes sense. I don’t have a permanent setup yet but I am working on that. It will be my first SCT though so lots to learn I am sure after the initial excitement. Do you image with the reducer or use it at native? Thanks 

I actually image both native and with the reducer depending on target.

That said f10 imaging will take you a long time to get enough data , especially when you dont get a lot of good clear nights.

Going forward I dont see me imaging at f10 very often except on the moon. I use a 2x Powermate to image bright planets at f20.

 

If your new to SCT , I highly recommend using an OAG not a guidescope. The Celeston OAG has a nice large prism compared to others.

[Simon Pepper]

14 minutes ago, fifeskies said:

I actually image both native and with the reducer depending on target.

That said f10 imaging will take you a long time to get enough data , especially when you dont get a lot of good clear nights.

Going forward I dont see me imaging at f10 very often except on the moon. I use a 2x Powermate to image bright planets at f20.

 

If your new to SCT , I highly recommend using an OAG not a guidescope. The Celeston OAG has a nice large prism compared to others.

Thanks and point noted thankfully I do use an OAG so hopefully shouldn’t be too difficult to transition. Was lucky enough to get the reducer as well so will keep that on as you say not enough clear nights at f10! Decent comparison image above as well it does look quite a lot larger that the 8! 

[fifeskies]

8 minutes ago, Simon Pepper said:

Thanks and point noted thankfully I do use an OAG so hopefully shouldn’t be too difficult to transition. Was lucky enough to get the reducer as well so will keep that on as you say not enough clear nights at f10! Decent comparison image above as well it does look quite a lot larger that the 8! 

I started of with the 290mm in my OAG , but it was a struggle esp at f10 to find enough guidestars. I changed over to the 174mm and now never have any issues.

[david_taurus83]

51 minutes ago, Simon Pepper said:

I have a 9.25 on the way and I am so excited. Will you use bobs knobs or do they hold colimation well? Thanks 

I have just got a C8 Edge. Haven't had the chance to set it up yet but it has Bob's Knobs fitted. They feel tight from previous owner and they prob do the job well enough but I will be changing mine to cap head bolts. I reckon you would get a better feeling of torque and more control from an allen key. Will be on a pier so hopefully should only need collimating the once.

[Stu]

40 minutes ago, david_taurus83 said:

I have just got a C8 Edge. Haven't had the chance to set it up yet but it has Bob's Knobs fitted. They feel tight from previous owner and they prob do the job well enough but I will be changing mine to cap head bolts. I reckon you would get a better feeling of torque and more control from an allen key. Will be on a pier so hopefully should only need collimating the once.

I think with an SCT that makes sense. Bob’s Knobs make collimating easier but you are likely to have to do it more often. If you get it accurate, and nice and tight with bolts then it should hold better.

[Elp]

2 hours ago, fifeskies said:

That said f10 imaging will take you a long time to get enough data , especially when you dont get a lot of good clear nights.

Maybe consider a Hyperstar. It's my main config with the C6, every other scope/combo is too slow in comparison. But if you want resolution then you have to go down the reducer route.

[Elp]

... what's happening with the 8 then.

[fifeskies]

16 minutes ago, Elp said:

... what's happening with the 8 then.

It will soon be for sale (with reducer and dewshield), but want to check out the 9.25 on a few targets first.