Sky-watcher Newt 200 PDS vs GSO for astrophotography

[ozboyz1]

Hi,

From advice in the other discussion thread, I was determined to get the Sky-watcher 8" PDS scope. Unfortunately, the distributors in Australia ran out of stock and the product code from a number of retailers got mixed up (... Is it too hard to use the manufacturer PID for the sake of consistency ??? ... this is something I don't understand) ......anyway, cut long story short, the promise was .... wait another month for new shipment, and there is no guarantee for it.

One of the retailer offer me the so called "equivalent GSO dual speed focuser" tube. Since I have great feedback from the forum for the Sky-watcher, I'm just wondering if anyone has tried to compare the 2 tubes?

Many thanks in advance. 

[Apharov]

I was also offered the GSO instead of SW when I was buying (from Germany), and tried to find comparisons. I couldn't find any thorough analysis, but the general feeling seemed to be that they're both optically ok, but mechanically the GSO is weaker than the SW. That would mean more problems in maintaining collimation and even tube flexure when attaching heavy cameras on the focuser.

Eventually I found a supplier who had the 200PDS in stock and got that. I've been happy with it.

[laser_jock99]

I have four GSO Newts but only one Skywatcher tube (ED80). At this end of the budget range there is not much to choose between them. Optically they should be much the same, mechanically GSO might have the edge- for two reasons. The mirror cell lends itself to much easier modification- adding stronger collimation springs is a common upgrade. I like the GSO focuser better too- it has a liner monorail design and is fairly stable.

http://www.teleskop-express.de/shop/product_info.php/info/p3700_M-LRN-Monorail-2--Newtonian-focuser---high-load-3kg--1-10-Micro-Transmission.html

For me the focuser would swing it, but otherwise there's not really a lot between them.

[Apharov]

 I like the GSO focuser better too- it has a liner monorail design and is fairly stable.

http://www.teleskop-express.de/shop/product_info.php/info/p3700_M-LRN-Monorail-2--Newtonian-focuser---high-load-3kg--1-10-Micro-Transmission.html

For me the focuser would swing it, but otherwise there's not really a lot between them.

If we're talking about the same GSO 200mm in the 200PDS price range (http://www.teleskop-express.de/shop/product_info.php/language/en/info/p49_GSO-200mm-f-5-Newton-OTA---94--Parabol-Spiegel---2--Crayford.html) I think it doesn't have the monorail focuser. The screws are not the same as in the separate product picture, and there's no mention of the mono rail on the OTA product page.

[laser_jock99]

If we're talking about the same GSO 200mm in the 200PDS price range (http://www.teleskop-express.de/shop/product_info.php/language/en/info/p49_GSO-200mm-f-5-Newton-OTA---94--Parabol-Spiegel---2--Crayford.html) I think it doesn't have the monorail focuser. The screws are not the same as in the separate product picture, and there's no mention of the mono rail on the OTA product page.

You might be right. The GSO F4 Astrograph Newts which I own all have the monorail focuser

http://www.teleskop-express.de/shop/product_info.php/info/p4762_GSO-6--Imaging-Newtonian---6--f-4---2--Monorail-focuser.html

I'm not sure about the other Newts now- they are a bit cheaper so might have a normal Crayford.

[GuillermoBarrancos]

If I would buy a large newt like that for imaging. I would buy the Carbon fiber ones, like TS/GSO CF or the SW Quattro CF.

[lensman57]

Hi,

From advice in the other discussion thread, I was determined to get the Sky-watcher 8" PDS scope. Unfortunately, the distributors in Australia ran out of stock and the product code from a number of retailers got mixed up (... Is it too hard to use the manufacturer PID for the sake of consistency ??? ... this is something I don't understand) ......anyway, cut long story short, the promise was .... wait another month for new shipment, and there is no guarantee for it.

One of the retailer offer me the so called "equivalent GSO dual speed focuser" tube. Since I have great feedback from the forum for the Sky-watcher, I'm just wondering if anyone has tried to compare the 2 tubes?

Many thanks in advance. 

Optically they are comparable, SW reputedly has the better tube, GSO by all accounts has a better focuser. At this price range there is not going to be a monumental performance difference between the two brands if any. I do not own any GSO products BTW, I have an SW Quattro 8s, SW 150 PDS , SW ED80,  SW 100ED DS PRO and an Ascesion 80 mm APO Triplet, just to make matters clear.

A.G

[ozboyz1]

The only astrophotography Sky-watcher OTA available in Australia is the Carbon Fibre one, 200mm F/4. I'm just wondering if this fast tube is suitable for observing?

Is there any 'gotcha' I need to look out for when changing from F/5 to F/4 (such as EP, filter, coma corrector, collimation etc)

Thanks again.

[GuillermoBarrancos]

The only astrophotography Sky-watcher OTA available in Australia is the Carbon Fibre one, 200mm F/4. I'm just wondering if this fast tube is suitable for observing?

Is there any 'gotcha' I need to look out for when changing from F/5 to F/4 (such as EP, filter, coma corrector, collimation etc)

Thanks again.

You can definitely use it for observing. Tho your collimation skills need to be up to snuff and it will be more demanding on your EP's.

( I.e. A lot of the (custom) truss dob designs are also F/4. )

[ozboyz1]

Sub Dwarf, 

sorry that I'm bit slow :-) can you explain about the demand on EP's with the F/4 ? Thanks.

[GuillermoBarrancos]

Sub Dwarf, 

sorry that I'm bit slow :-) can you explain about the demand on EP's with the F/4 ? Thanks.

The general rule is that when you start getting below F/5, you will need better "premium" quality EP's. Tho it varies from person to person in how distracted you get from sertain optical errors that will start to become more prominent in cheaper EP's at fast focal ratios.

[Apharov]

I also considered getting an F/4 Newt instead of the F/5. The general opinion at that time seemed to be that F/5 is significantly easier on medium-priced eyepieces and it has much less collimation woes. Given that I need to setup from scratch each time and the F/5 scope "only" needs roughly 60% longer exposures than the F/4 I went with the F/5.