Hi Tatyana - thanks for the reply. It's helpful to see the calculation. Let's keep the maths simple!

At around 47-48 North, 00 Pisces is on the MC and 00 Cancer rises. This means that the angle MC-ASC is 120 degrees (DSA - diurnal semi-arc) and angle ASC-IC is 60 degrees (nocturnal semi-arc).

Six equal divisions of the DSA = 20 degrees per division.

Six equal divisions of the NSA = 10 degrees per division.

Now Porphyry makes 3 equal divisions of the same arcs.

So with Porphyry we have three equal divisions of the DSA = 40 degrees per division.

Three equal divisions of the NSA = 20 degrees per division.

Now Porphyry cusps are:

H1 = 00 Cancer

H2 = 20 Cancer

H3 = 10 Leo

H4 = 00 Virgo

H5 = 10 Libra

H6 = 20 Scorpio

H7 = 00 Capricorn

H8 = 20 Capricorn

H9 = 10 Aquarius

H10 = 00 Pisces

H11 = 10 Aries

H12 = 20 Taurus

Your cusps are:

H1 = 10 Gemini

H2 = 10 Cancer

H3 = 00 Leo

H4 = 20 Leo

H5 = 20 Virgo

H6 = 00 Scorpio

H7 = 10 Sagittarius

H8 = 10 Capricorn

H9 = 00 Aquarius

H10 = 20 Aquarius

H11 = 20 Pisces

H12 = 00 Taurus

Now midpoint Porphyry houses:

H1 = 00 Cancer (10 Cancer)

H2 = 20 Cancer (00 Leo)

H3 = 10 Leo (20 Leo)

H4 = 00 Virgo (20 Virgo)

H5 = 10 Libra (00 Scorpio)

H6 = 20 Scorpio (10 Sagittarius)

H7 = 00 Capricorn (10 Capricorn)

H8 = 20 Capricorn (00 Aquarius)

H9 = 10 Aquarius (20 Aquarius)

H10 = 00 Pisces (20 Pisces)

H11 = 10 Aries (00 Taurus)

H12 = 20 Taurus (10 Gemini)

Please do check my calculations and accept my apologies if I have not fully understood your reasoning. However, I think it is very likely that the 'cusps' you have been using are the midpoints of the Porphyry houses.

The following chart is cast for the approximate latitude that gives the cusps above in Porphyry.

The following chart is cast for the same latitude with Sripati.

I think Chris is right that you have been using Sripati cusps which are the midpoints of the Porphyry houses.

I hope that helps. Thanks for your interest in Planetdance.

Ed