Comparing telescope

[jeffrahiabc]

Hi everyone 

I am bit confused which scope to choose from these 4 telescope. 

can somebody please help me thank you

1) Celestron CPC800 GPS

2)Meade LX90 8" ACF

3)Celestron Nexstar 8se  

4)Celestron C8 on Advanced VX mount

[PeterCPC]

Hello and welcome.

You will need to give a bit more information first. What do you want to do - visual or astrophotography? If AP do you want to image planets or deep space objects? That would help to inform the choices.

Peter

[jeffrahiabc]

1 minute ago, PeterCPC said:

Hello and welcome.

You will need to give a bit more information first. What do you want to do - visual or astrophotography? If AP do you want to image planets or deep space objects? That would help to inform the choices.

Peter

 

Thank you Peter Mostly for visual purpose, May take some picture in future not now. planets are main target to view, As i am buying that as a gift for someone

[alanjgreen]

Of those listed, the cpc800 is the best scope for visual. It's dual fork mount is rock solid.

i would avoid the Meade, their SCTs are not as good as Celestron. The focuser is not as good and mirror flop comments seem to affect even the 8".

the avx is an EQ mount for photography so if you are visual then knock that one out. EQ mounts are harder to setup and the eyepiece can end up anywhere! It will also take 3 trips out to the garden to get all the bits outside for assembly each time.

the 8se is a nice scope. It is only single fork mount so will be subject to an amount of wobble. It is not as stable as the cpc800. It is cheaper and there is a reason it is cheaper !

I had a cpc800 and it is a great all round scope, easy to setup, easy to use. Rock solid in the wind. I upgraded mine to the larger cpc1100 so it must have being doing something right. If you are going to try some photos then the stronger dual fork will be a good choice.

There is a 2nd hand one on astrobuysell (in Kent) if that's any good to you? It's a bargain at that price!

http://www.astrobuysell.com/uk/propview.php?view=123290

Any other questions?

Alan

[PeterCPC]

I would concur with Alan. I had a CPC800 and it was great for visual use and planetary AP.

Peter

[jeffrahiabc]

43 minutes ago, alanjgreen said:

Of those listed, the cpc800 is the best scope for visual. It's dual fork mount is rock solid.

i would avoid the Meade, their SCTs are not as good as Celestron. The focuser is not as good and mirror flop comments seem to affect even the 8".

the avx is an EQ mount for photography so if you are visual then knock that one out. EQ mounts are harder to setup and the eyepiece can end up anywhere! It will also take 3 trips out to the garden to get all the bits outside for assembly each time.

the 8se is a nice scope. It is only single fork mount so will be subject to an amount of wobble. It is not as stable as the cpc800. It is cheaper and there is a reason it is cheaper !

I had a cpc800 and it is a great all round scope, easy to setup, easy to use. Rock solid in the wind. I upgraded mine to the larger cpc1100 so it must have being doing something right. If you are going to try some photos then the stronger dual fork will be a good choice.

There is a 2nd hand one on astrobuysell (in Kent) if that's any good to you? It's a bargain at that price!

http://www.astrobuysell.com/uk/propview.php?view=123290

Any other questions?

Alan

 

Thank you Alan i will go for cpc

[jeffrahiabc]

40 minutes ago, PeterCPC said:

I would concur with Alan. I had a CPC800 and it was great for visual use and planetary AP.

Peter

 

thanks peter 

[jeffrahiabc]

2 hours ago, alanjgreen said:

Of those listed, the cpc800 is the best scope for visual. It's dual fork mount is rock solid.

i would avoid the Meade, their SCTs are not as good as Celestron. The focuser is not as good and mirror flop comments seem to affect even the 8".

the avx is an EQ mount for photography so if you are visual then knock that one out. EQ mounts are harder to setup and the eyepiece can end up anywhere! It will also take 3 trips out to the garden to get all the bits outside for assembly each time.

the 8se is a nice scope. It is only single fork mount so will be subject to an amount of wobble. It is not as stable as the cpc800. It is cheaper and there is a reason it is cheaper !

I had a cpc800 and it is a great all round scope, easy to setup, easy to use. Rock solid in the wind. I upgraded mine to the larger cpc1100 so it must have being doing something right. If you are going to try some photos then the stronger dual fork will be a good choice.

There is a 2nd hand one on astrobuysell (in Kent) if that's any good to you? It's a bargain at that price!

http://www.astrobuysell.com/uk/propview.php?view=123290

Any other questions?

Alan

 

Hi alan

I had a looked at the link you send.

on that website, i found another one also what you think about that is it reasonable link is below?

 What to check when buying cpc800 what are the most common issue to look for?

http://www.astrobuysell.com/uk/propview.php?view=120515

[alanjgreen]

Cpc800 or cpc925 - you can't go wrong with either!

if you contact the seller of the 925 then ask her about the comments she makes re: fitting the two scope sections together. Neither of my cpcs have had this issue. But it may be nothing.

the CPC scopes are best transported sitting on the passenger seat of your car (they are small child size). Take a length of rope (10-12 ft), then use the rope to secure the CPC to your headrest. Put the seatbelt on and it will be fine to travel  

just check the weights, the 925 is a bigger tube on a bigger mount and if I remember correctly quite a bit heavier than the 800. You said you were buying for someone else, if a lady then I would go for the smaller 800.

925 = 58lbs, 800 = 42lbs ( combined tripod plus scope, you take them outside in 2 trips, tripod which you level using the built in spirit level, then scope. They are easy to carry, Celestron has put 2 well placed hand holes that makes it easy)

the 2nd hand 925 comes with a dew shield, saves you buying one. The 800 does not so will need o buy one. The Celestron model from Harrison telescopes works out the cheapest. They are all the same so just buy the cheapest. You must have one or the scope front glass plate will dew over after an hour ending your session. It's not a problem once the scope is brought inside, it will just evaporate away. All mak and sct style scopes suffer from this.

https://www.harrisontelescopes.co.uk/acatalog/Celestron_Dew_Shield_6____8__SCT.html#SID=24

https://www.firstlightoptics.com/dew-prevention/astrozap-flexible-dew-shield.html

the 800 will take longer to dew over than the 925 and depending on whether you are in the countryside then the 925 will also need a heater tape which will also need connecting to your 12v supply.

[alanjgreen]

46 minutes ago, jeffrahiabc said:

What to check when buying cpc800 what are the most common issue to look for?

1. You want to see the scope working, powered up. Move it left, right, up,down. Seller should be able to perform a fake solar system align to get the scope "tracking" , put your ear to the scope and hear the motors quietly working as the scope tracks the fake object.

2. Check the front of the scope for scratches. Expect to see dust deposits, but there should not be any oily stains or similar. The corrector plate (glass front) is easily cleaned with care and the right stuff but it must be removed from the scope to clean so best only done when really necessary. They have to be really dirty to affect the view.

3. If in daylight, then get the scope setup and look through it at a distant object. Image will be upside down and reversed so expect to be confused by what you see. But does the image look sharp all over. Any blotches or marks in the view?

4. Make a list of the original extras that came with the scope, make sure you are getting them all. Finder scope, diagonal, eyepiece, handset, pc serial cable, power cable.

Power cable will terminate in cigarette lighter. All scope stuff uses these sockets, you will need to buy a power tank to power the scope, something like this

https://www.firstlightoptics.com/batteries-powerpacks/skywatcher-powertank-17ah.html

get one with reasonable Ah capacity otherwise you will always be running out of power. A bigger one will also run a heater tape as well should you need to add one in the winter months.

[ronin]

I would say the C8 on the AVX, over the CPC.

Reason simply because you then have an eqiuitorial mount that will do visual and AP if you or whoever goes down that route, and many (most) do at sometime. If it was to be visual and only ever visual then the CPC. However I suspect that "visual only, ever" is not applicable. It rarely is.

With the AVX you/they can get a smaller scope more suited to imaging and use that on the mount, or do visual with the C8.

In effect a bit more flexibility.

[iapa]

5 hours ago, alanjgreen said:

the avx is an EQ mount for photography so if you are visual then knock that one out. EQ mounts are harder to setup and the eyepiece can end up anywhere! It will also take 3 trips out to the garden to get all the bits outside for assembly each time.

I would opt for the AVX as well as @ronin.

If you were using a reflector of image, then yes, the eyepiece can end up at a position you see unless you are a stork.

However, all of your proposed options are all SCT where the eyepiece is at the rear. True if you are using a right angle you may need to adjust now and again, but not as badly as with a reflector.

I dont see that EQ is much harder to set up.

All of the mounts are goto, and polar alignment for visual does not need to be as accurate as for imaging. The 12-13lb. with of the SCT is well within the capacity of the AVX. Although I'd not suggest using that tube for imaging with out focal reducers and large pixel camera sensors.

I keep the mount assembled in the lounge front room (which opens to the back of the house toto) and just carry out out then second trip for the tube. It's bulky but the 46lb. is fairly manageable- then I am only moving it about 20' and down three steps.

[jeffrahiabc]

18 hours ago, alanjgreen said:

Cpc800 or cpc925 - you can't go wrong with either!

if you contact the seller of the 925 then ask her about the comments she makes re: fitting the two scope sections together. Neither of my cpcs have had this issue. But it may be nothing.

the CPC scopes are best transported sitting on the passenger seat of your car (they are small child size). Take a length of rope (10-12 ft), then use the rope to secure the CPC to your headrest. Put the seatbelt on and it will be fine to travel  

just check the weights, the 925 is a bigger tube on a bigger mount and if I remember correctly quite a bit heavier than the 800. You said you were buying for someone else, if a lady then I would go for the smaller 800.

925 = 58lbs, 800 = 42lbs ( combined tripod plus scope, you take them outside in 2 trips, tripod which you level using the built in spirit level, then scope. They are easy to carry, Celestron has put 2 well placed hand holes that makes it easy)

the 2nd hand 925 comes with a dew shield, saves you buying one. The 800 does not so will need o buy one. The Celestron model from Harrison telescopes works out the cheapest. They are all the same so just buy the cheapest. You must have one or the scope front glass plate will dew over after an hour ending your session. It's not a problem once the scope is brought inside, it will just evaporate away. All mak and sct style scopes suffer from this.

https://www.harrisontelescopes.co.uk/acatalog/Celestron_Dew_Shield_6____8__SCT.html#SID=24

https://www.firstlightoptics.com/dew-prevention/astrozap-flexible-dew-shield.html

the 800 will take longer to dew over than the 925 and depending on whether you are in the countryside then the 925 will also need a heater tape which will also need connecting to your 12v supply.

Thanks Alan 

Yes it is for lady, I am considering 8inch.

Thanks for link Harrison is out of stock i will email them to find out when they get in stock if not then i will buy from FLO.

what is heater tape ? 8" not required heater tape ?

 

[jeffrahiabc]

18 hours ago, alanjgreen said:

1. You want to see the scope working, powered up. Move it left, right, up,down. Seller should be able to perform a fake solar system align to get the scope "tracking" , put your ear to the scope and hear the motors quietly working as the scope tracks the fake object.

2. Check the front of the scope for scratches. Expect to see dust deposits, but there should not be any oily stains or similar. The corrector plate (glass front) is easily cleaned with care and the right stuff but it must be removed from the scope to clean so best only done when really necessary. They have to be really dirty to affect the view.

3. If in daylight, then get the scope setup and look through it at a distant object. Image will be upside down and reversed so expect to be confused by what you see. But does the image look sharp all over. Any blotches or marks in the view?

4. Make a list of the original extras that came with the scope, make sure you are getting them all. Finder scope, diagonal, eyepiece, handset, pc serial cable, power cable.

Power cable will terminate in cigarette lighter. All scope stuff uses these sockets, you will need to buy a power tank to power the scope, something like this

https://www.firstlightoptics.com/batteries-powerpacks/skywatcher-powertank-17ah.html

get one with reasonable Ah capacity otherwise you will always be running out of power. A bigger one will also run a heater tape as well should you need to add one in the winter months.

Alan you made my life easy thank you

if glass is oily what that mean scope is bad ?

 

[jeffrahiabc]

17 hours ago, ronin said:

I would say the C8 on the AVX, over the CPC.

Reason simply because you then have an eqiuitorial mount that will do visual and AP if you or whoever goes down that route, and many (most) do at sometime. If it was to be visual and only ever visual then the CPC. However I suspect that "visual only, ever" is not applicable. It rarely is.

With the AVX you/they can get a smaller scope more suited to imaging and use that on the mount, or do visual with the C8.

In effect a bit more flexibility.

Hi Ronin 

Thank you i will consider that but my problem is i do not know how many things needed to complete the scope.

Preferable if there is a setup made by someone and i just buy it.

[jeffrahiabc]

What kind of Eyepieces,filters and other accessories required with 8" as there is nothing extra coming with 8" just standard factory stuff

[alanjgreen]

1 hour ago, jeffrahiabc said:

Thanks for link Harrison is out of stock i will email them to find out when they get in stock if not then i will buy from FLO.

what is heater tape ? 8" not required heater tape ?

 

SCT scopes are solid tubes, the air inside is trapped and cannot get out. When the scope is used on a cold night the air inside will cool down and the front of the scope will "dew" up. A heater tape can be wrapped around the outside of the scope and it applies a very small amount of heat to the scope body. The heat is enough to keep the air inside above 0 and the scope front stays nice and clear all night.

I know people in Cumbria with 8" that are using a tape - but it gets cold up here. Depends where you are? Start with the dew shield (you WILL need this) then ADD a tape if dew starts to be a problem. If you are out for 60-90 mins then a dew shield should be fine on its own. But longer sessions or coldest nights may need a tape fitted too.

example: My 11" CPC needs TWO heater tapes fitted for me to maintain a clear view for 4+ hours observing. One runs on full power and the other uses a variable voltage so I start with it off, then add more as the night goes on.

Here is a pic of my scope, you can see the two heater tapes wrapped around the front on the outside... You can see my refractor on top also has a heater tape and its only 4"

 

[alanjgreen]

1 hour ago, jeffrahiabc said:

if glass is oily what that mean scope is bad ?

No it does not. It just means that it WILL need a clean as it may attract fungus that can eat the coatings on the glass.

If you use the correct cleaner and cotton balls, take it nice and steady and follow a documented set of cleaning steps, it will come up as good as new. The coatings on the corrector plate (front glass) are pretty tough.

 

[Cosmic Geoff]

12v battery or equivalent, dew shield, stool to sit on.

As for eyepieces, asides from the 25mm I'd suggest a 15mm Plossl and an 8mm or 10mm of good quality. Filters - don't bother until you meet a specific need. You don't need a Moon filter - I have never felt the need for one. Advice will inevitably vary. For an 8"SCT with a f10 focal ratio and a 2 metre focal length, there is no need to go flashing the plastic for exotic eyepieces. 

[alanjgreen]

1 hour ago, jeffrahiabc said:

What kind of Eyepieces,filters and other accessories required with 8" as there is nothing extra coming with 8" just standard factory stuff

You need the DEW SHIELD & POWER TANK only.

More eyepieces can be added but not essential before you even use the scope. Although with only one supplied, you may wish to add another, let me explain...

The eyepieces have numbers on the side such as 25mm or 10mm. This number allows you to calc the magnification that that eyepiece will give in your scope.

I can see that the scope comes with a 40mm eyepiece (this is actually a decent eyepiece (EP) so plan on keeping it). The scope has a focal length of 2050mm (this means that if it was a reflector/refractor style then the tube would be 2050mm long! SCT scopes have a magnifier secondary mirror that allows the tube to be shortened by x5.

Anyway, if we diviide 2050/40 we get 51 answer. The 40mm eyepiece will give x51 magnification in that scope. This is a nice magnification for star clusters and the milky way in the summer.

You should plan long term for a nice spread of magnifications in steps of x50 (so x100, x150, x200, x250). UK atmosphere makes magnification above this pretty useless as you will not be able to get a sharp focus due to atmospheric conditions.

Planets need x150 - x250, Moon can take plenty of magnification.

Galaxies need x100 - x150

Globular clusters can take x200

So if adding a second, then go for x150 which is (2050/150= 13mm), something like a 12mm celestron xcel-lx (good value eyepiece)

https://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

If you wear glasses then the only thing is to check "eye relief" when purchasing eyepieces and you want mininum 15mm eye relief for glasses.

 

Finally, a nebula filter (called a UHC filter) will work well in your scope. But leave this until the summer when there are more nebulas in the night sky. And remember the golden rule of nebula filters = "you get what you pay for" although the skywatcher UHC is pretty good for what it costs.

https://www.firstlightoptics.com/uhc-oiii-visual-filters/skywatcher-uhc-filter.html

 

Then (thanks to cosmic geoff) there are moon filters. Unlike Geoff, I find i "do" need a moon filter as my eyes must be more sensitive, anyway if you find you need one then the Baader is the best one (you need the 0.9 version)

https://www.firstlightoptics.com/moon-neutral-density-filters/baader-neutral-density-moon-filters.html

You can test out whether you would prefer a moon filter by simply trying to view the moon while wearing SUNGLASSES, if you like that view better then buy a moon filter

[jeffrahiabc]

10 hours ago, alanjgreen said:

SCT scopes are solid tubes, the air inside is trapped and cannot get out. When the scope is used on a cold night the air inside will cool down and the front of the scope will "dew" up. A heater tape can be wrapped around the outside of the scope and it applies a very small amount of heat to the scope body. The heat is enough to keep the air inside above 0 and the scope front stays nice and clear all night.

I know people in Cumbria with 8" that are using a tape - but it gets cold up here. Depends where you are? Start with the dew shield (you WILL need this) then ADD a tape if dew starts to be a problem. If you are out for 60-90 mins then a dew shield should be fine on its own. But longer sessions or coldest nights may need a tape fitted too.

example: My 11" CPC needs TWO heater tapes fitted for me to maintain a clear view for 4+ hours observing. One runs on full power and the other uses a variable voltage so I start with it off, then add more as the night goes on.

Here is a pic of my scope, you can see the two heater tapes wrapped around the front on the outside... You can see my refractor on top also has a heater tape and its only 4"

 

Thanks for detail explanation 

[jeffrahiabc]

10 hours ago, alanjgreen said:

No it does not. It just means that it WILL need a clean as it may attract fungus that can eat the coatings on the glass.

If you use the correct cleaner and cotton balls, take it nice and steady and follow a documented set of cleaning steps, it will come up as good as new. The coatings on the corrector plate (front glass) are pretty tough.

 

Alan which one is good glass cleaner ?

[jeffrahiabc]

10 hours ago, Cosmic Geoff said:

12v battery or equivalent, dew shield, stool to sit on.

As for eyepieces, asides from the 25mm I'd suggest a 15mm Plossl and an 8mm or 10mm of good quality. Filters - don't bother until you meet a specific need. You don't need a Moon filter - I have never felt the need for one. Advice will inevitably vary. For an 8"SCT with a f10 focal ratio and a 2 metre focal length, there is no need to go flashing the plastic for exotic eyepieces. 

Thanks Geoff, for Celestron cpc 8" scope Only Celestron lens can be used  or any telescope lens?

[jeffrahiabc]

11 hours ago, alanjgreen said:

You need the DEW SHIELD & POWER TANK only.

More eyepieces can be added but not essential before you even use the scope. Although with only one supplied, you may wish to add another, let me explain...

The eyepieces have numbers on the side such as 25mm or 10mm. This number allows you to calc the magnification that that eyepiece will give in your scope.

I can see that the scope comes with a 40mm eyepiece (this is actually a decent eyepiece (EP) so plan on keeping it). The scope has a focal length of 2050mm (this means that if it was a reflector/refractor style then the tube would be 2050mm long! SCT scopes have a magnifier secondary mirror that allows the tube to be shortened by x5.

Anyway, if we diviide 2050/40 we get 51 answer. The 40mm eyepiece will give x51 magnification in that scope. This is a nice magnification for star clusters and the milky way in the summer.

You should plan long term for a nice spread of magnifications in steps of x50 (so x100, x150, x200, x250). UK atmosphere makes magnification above this pretty useless as you will not be able to get a sharp focus due to atmospheric conditions.

Planets need x150 - x250, Moon can take plenty of magnification.

Galaxies need x100 - x150

Globular clusters can take x200

So if adding a second, then go for x150 which is (2050/150= 13mm), something like a 12mm celestron xcel-lx (good value eyepiece)

https://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

If you wear glasses then the only thing is to check "eye relief" when purchasing eyepieces and you want mininum 15mm eye relief for glasses.

 

Finally, a nebula filter (called a UHC filter) will work well in your scope. But leave this until the summer when there are more nebulas in the night sky. And remember the golden rule of nebula filters = "you get what you pay for" although the skywatcher UHC is pretty good for what it costs.

https://www.firstlightoptics.com/uhc-oiii-visual-filters/skywatcher-uhc-filter.html

 

Then (thanks to cosmic geoff) there are moon filters. Unlike Geoff, I find i "do" need a moon filter as my eyes must be more sensitive, anyway if you find you need one then the Baader is the best one (you need the 0.9 version)

https://www.firstlightoptics.com/moon-neutral-density-filters/baader-neutral-density-moon-filters.html

You can test out whether you would prefer a moon filter by simply trying to view the moon while wearing SUNGLASSES, if you like that view better then buy a moon filter

Thank Alan thats brilliant explanation about lens.

its a  great help from you

So its mean if i want to add for planet which is x250 magnifications correct me if i am wrong

For planet 2050/250 = 8.2mm lens i required correct? 

for galexy 2050/150 = 13.7mm lense ?

Cluster 2050/200 = 10.25mm lense ?

i looked up UHC filter there are two size 1.25" and 2" which one will go to my scope? you said you get what you pay for in UHC filters are their different type or quality? what exactly those filter do make picture clear or stop some kind of harmful rays ets?

what that mean in moon filter 0.9 density 3.0 (strongest) and what size will i need 1.25" or 2"?

I Heard about Celestron Lens kit is that any good or just waste of money ?

what is the main difference between following link kit and the link you send me ?

something like this

http://www.ebay.co.uk/itm/262851426973?_trksid=p2055359.m2763.l2649&ssPageName=STRK%3AMEBIDX%3AIT 

[Dave In Vermont]

In the defense of Meade SCT's, their optical quality is outstanding. It's their mechanical peripherals (focusers, clutch-gearing interface, etc.) that give them a 'black-eye.' If you're good with tools and mechanics in general, they're great if you roll-up your sleeves and tackle the mechanical problems with available kits. Or invent your own. Celestron has a few 'loose-screws' in their mechanical side as well - so I've heard.

Dave - Brave Meade-Owner & Mechanic